diff --git a/v2rayN/v2rayN/Base/HttpClientHelper.cs b/v2rayN/v2rayN/Base/HttpClientHelper.cs
index a3bacb5d..06c67160 100644
--- a/v2rayN/v2rayN/Base/HttpClientHelper.cs
+++ b/v2rayN/v2rayN/Base/HttpClientHelper.cs
@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Net;
 using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Threading;
@@ -58,7 +57,7 @@ namespace v2rayN.Base
             HttpResponseMessage response = await client.GetAsync(url, token);
             if (!response.IsSuccessStatusCode)
             {
-                throw new Exception(string.Format("The request returned with HTTP status code {0}", response.StatusCode));
+                throw new Exception($"The request returned with HTTP status code {response.StatusCode}");
             }
             return await response.Content.ReadAsStringAsync();
         }
@@ -77,11 +76,11 @@ namespace v2rayN.Base
         {
             if (string.IsNullOrEmpty(url))
             {
-                throw new ArgumentNullException("url");
+                throw new ArgumentNullException(nameof(url));
             }
             if (string.IsNullOrEmpty(fileName))
             {
-                throw new ArgumentNullException("fileName");
+                throw new ArgumentNullException(nameof(fileName));
             }
             if (File.Exists(fileName))
             {
@@ -92,59 +91,55 @@ namespace v2rayN.Base
 
             if (!response.IsSuccessStatusCode)
             {
-                throw new Exception(string.Format("The request returned with HTTP status code {0}", response.StatusCode));
+                throw new Exception($"The request returned with HTTP status code {response.StatusCode}");
             }
 
-            var total = response.Content.Headers.ContentLength.HasValue ? response.Content.Headers.ContentLength.Value : -1L;
+            var total = response.Content.Headers.ContentLength ?? -1L;
             var canReportProgress = total != -1 && progress != null;
 
-            using (var stream = await response.Content.ReadAsStreamAsync())
+            using var stream = await response.Content.ReadAsStreamAsync();
+            using var file = File.Create(fileName);
+            var totalRead = 0L;
+            var buffer = new byte[1024 * 1024];
+            var isMoreToRead = true;
+            var progressPercentage = 0;
+
+            do
             {
-                using (var file = File.Create(fileName))
+                token.ThrowIfCancellationRequested();
+
+                var read = await stream.ReadAsync(buffer, 0, buffer.Length, token);
+
+                if (read == 0)
                 {
-                    var totalRead = 0L;
-                    var buffer = new byte[1024 * 1024];
-                    var isMoreToRead = true;
-                    var progressPercentage = 0;
+                    isMoreToRead = false;
+                }
+                else
+                {
+                    var data = new byte[read];
+                    buffer.ToList().CopyTo(0, data, 0, read);
 
-                    do
-                    {
-                        token.ThrowIfCancellationRequested();
+                    // TODO: put here the code to write the file to disk
+                    await file.WriteAsync(data, 0, read, token);
 
-                        var read = await stream.ReadAsync(buffer, 0, buffer.Length, token);
+                    totalRead += read;
 
-                        if (read == 0)
-                        {
-                            isMoreToRead = false;
-                        }
-                        else
-                        {
-                            var data = new byte[read];
-                            buffer.ToList().CopyTo(0, data, 0, read);
-
-                            // TODO: put here the code to write the file to disk
-                            file.Write(data, 0, read);
-
-                            totalRead += read;
-
-                            if (canReportProgress)
-                            {
-                                var percent = Convert.ToInt32((totalRead * 1d) / (total * 1d) * 100);
-                                if (progressPercentage != percent && percent % 10 == 0)
-                                {
-                                    progressPercentage = percent;
-                                    progress.Report(percent);
-                                }
-                            }
-                        }
-                    } while (isMoreToRead);
-                    file.Close();
                     if (canReportProgress)
                     {
-                        progress.Report(101);
-
+                        var percent = Convert.ToInt32((totalRead * 1d) / (total * 1d) * 100);
+                        if (progressPercentage != percent && percent % 10 == 0)
+                        {
+                            progressPercentage = percent;
+                            progress.Report(percent);
+                        }
                     }
                 }
+            } while (isMoreToRead);
+            file.Close();
+            if (canReportProgress)
+            {
+                progress.Report(101);
+
             }
         }
 
@@ -152,68 +147,66 @@ namespace v2rayN.Base
         {
             if (string.IsNullOrEmpty(url))
             {
-                throw new ArgumentNullException("url");
+                throw new ArgumentNullException(nameof(url));
             }
 
             var response = await client.GetAsync(url, HttpCompletionOption.ResponseHeadersRead, token);
 
             if (!response.IsSuccessStatusCode)
             {
-                throw new Exception(string.Format("The request returned with HTTP status code {0}", response.StatusCode));
+                throw new Exception($"The request returned with HTTP status code {response.StatusCode}");
             }
 
             //var total = response.Content.Headers.ContentLength.HasValue ? response.Content.Headers.ContentLength.Value : -1L;
             //var canReportProgress = total != -1 && progress != null;
 
-            using (var stream = await response.Content.ReadAsStreamAsync())
+            using var stream = await response.Content.ReadAsStreamAsync();
+            var totalRead = 0L;
+            var buffer = new byte[1024 * 64];
+            var isMoreToRead = true;
+            string progressSpeed = string.Empty;
+            DateTime totalDatetime = DateTime.Now;
+
+            do
             {
-                var totalRead = 0L;
-                var buffer = new byte[1024 * 64];
-                var isMoreToRead = true;
-                string progressSpeed = string.Empty;
-                DateTime totalDatetime = DateTime.Now;
-
-                do
+                if (token.IsCancellationRequested)
                 {
-                    if (token.IsCancellationRequested)
+                    if (totalRead > 0)
                     {
-                        if (totalRead > 0)
-                        {
-                            return;
-                        }
-                        else
-                        {
-                            token.ThrowIfCancellationRequested();
-                        }
-                    }
-
-                    var read = await stream.ReadAsync(buffer, 0, buffer.Length, token);
-
-                    if (read == 0)
-                    {
-                        isMoreToRead = false;
+                        return;
                     }
                     else
                     {
-                        var data = new byte[read];
-                        buffer.ToList().CopyTo(0, data, 0, read);
+                        token.ThrowIfCancellationRequested();
+                    }
+                }
 
-                        // TODO:   
-                        totalRead += read;
+                var read = await stream.ReadAsync(buffer, 0, buffer.Length, token);
 
-                        TimeSpan ts = (DateTime.Now - totalDatetime);
-                        var speed = (totalRead * 1d / ts.TotalMilliseconds / 1000).ToString("#0.0");
-                        if (progress != null)
+                if (read == 0)
+                {
+                    isMoreToRead = false;
+                }
+                else
+                {
+                    var data = new byte[read];
+                    buffer.ToList().CopyTo(0, data, 0, read);
+
+                    // TODO:   
+                    totalRead += read;
+
+                    TimeSpan ts = (DateTime.Now - totalDatetime);
+                    var speed = (totalRead * 1d / ts.TotalMilliseconds / 1000).ToString("#0.0");
+                    if (progress != null)
+                    {
+                        if (progressSpeed != speed)
                         {
-                            if (progressSpeed != speed)
-                            {
-                                progressSpeed = speed;
-                                progress.Report(speed);
-                            }
+                            progressSpeed = speed;
+                            progress.Report(speed);
                         }
                     }
-                } while (isMoreToRead);
-            }
+                }
+            } while (isMoreToRead);
         }
 
     }
diff --git a/v2rayN/v2rayN/Base/ListViewFlickerFree.cs b/v2rayN/v2rayN/Base/ListViewFlickerFree.cs
index 94e803e9..9ac970cc 100644
--- a/v2rayN/v2rayN/Base/ListViewFlickerFree.cs
+++ b/v2rayN/v2rayN/Base/ListViewFlickerFree.cs
@@ -76,14 +76,7 @@ namespace v2rayN.Base
                 Rectangle itemBounds = GetItemRect(targetIndex);
                 EnsureVisible(targetIndex);
 
-                if (targetPoint.Y > itemBounds.Top + (itemBounds.Height / 2))
-                {
-                    InsertionMark.AppearsAfterItem = true;
-                }
-                else
-                {
-                    InsertionMark.AppearsAfterItem = false;
-                }
+                InsertionMark.AppearsAfterItem = targetPoint.Y > itemBounds.Top + (itemBounds.Height / 2);
             }
             InsertionMark.Index = targetIndex;
         }
diff --git a/v2rayN/v2rayN/Base/StringEx.cs b/v2rayN/v2rayN/Base/StringEx.cs
index 40544106..d7f95650 100644
--- a/v2rayN/v2rayN/Base/StringEx.cs
+++ b/v2rayN/v2rayN/Base/StringEx.cs
@@ -36,8 +36,7 @@ namespace v2rayN.Base
 
         public static IEnumerable<string> NonWhiteSpaceLines(this TextReader reader)
         {
-            string line;
-            while ((line = reader.ReadLine()) != null)
+            while (reader.ReadLine() is { } line)
             {
                 if (line.IsWhiteSpace()) continue;
                 yield return line;
diff --git a/v2rayN/v2rayN/Forms/AddServer2Form.cs b/v2rayN/v2rayN/Forms/AddServer2Form.cs
index 823f0137..3b419813 100644
--- a/v2rayN/v2rayN/Forms/AddServer2Form.cs
+++ b/v2rayN/v2rayN/Forms/AddServer2Form.cs
@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Diagnostics;
-using System.IO;
 using System.Windows.Forms;
 using v2rayN.Handler;
 using v2rayN.Mode;
diff --git a/v2rayN/v2rayN/Forms/AddServerForm.cs b/v2rayN/v2rayN/Forms/AddServerForm.cs
index c0f4459f..62f73d6c 100644
--- a/v2rayN/v2rayN/Forms/AddServerForm.cs
+++ b/v2rayN/v2rayN/Forms/AddServerForm.cs
@@ -1,5 +1,4 @@
 using System;
-using System.Collections.Generic;
 using System.Windows.Forms;
 using v2rayN.Handler;
 using v2rayN.Mode;
diff --git a/v2rayN/v2rayN/Forms/BaseServerForm.cs b/v2rayN/v2rayN/Forms/BaseServerForm.cs
index 9618c480..4abc06c8 100644
--- a/v2rayN/v2rayN/Forms/BaseServerForm.cs
+++ b/v2rayN/v2rayN/Forms/BaseServerForm.cs
@@ -1,6 +1,4 @@
-using System;
-using System.Windows.Forms;
-using v2rayN.Mode;
+using v2rayN.Mode;
 
 namespace v2rayN.Forms
 {
diff --git a/v2rayN/v2rayN/Forms/GlobalHotkeySettingForm.cs b/v2rayN/v2rayN/Forms/GlobalHotkeySettingForm.cs
index 0bf81688..f39ef1e4 100644
--- a/v2rayN/v2rayN/Forms/GlobalHotkeySettingForm.cs
+++ b/v2rayN/v2rayN/Forms/GlobalHotkeySettingForm.cs
@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.Windows.Forms;
-using v2rayN.Base;
 using v2rayN.Handler;
 using v2rayN.Mode;
 using v2rayN.Resx;
@@ -18,10 +17,7 @@ namespace v2rayN.Forms
 
         private void GlobalHotkeySettingForm_Load(object sender, EventArgs e)
         {
-            if (config.globalHotkeys == null)
-            {
-                config.globalHotkeys = new List<KeyEventItem>();
-            }
+            config.globalHotkeys ??= new List<KeyEventItem>();
 
             foreach (EGlobalHotkey it in Enum.GetValues(typeof(EGlobalHotkey)))
             {
diff --git a/v2rayN/v2rayN/Forms/GroupSettingControl.cs b/v2rayN/v2rayN/Forms/GroupSettingControl.cs
index 07abc73d..66b25794 100644
--- a/v2rayN/v2rayN/Forms/GroupSettingControl.cs
+++ b/v2rayN/v2rayN/Forms/GroupSettingControl.cs
@@ -1,7 +1,6 @@
 using System;
 using System.Windows.Forms;
 using v2rayN.Base;
-using v2rayN.Handler;
 using v2rayN.Mode;
 
 namespace v2rayN.Forms
diff --git a/v2rayN/v2rayN/Forms/GroupSettingForm.cs b/v2rayN/v2rayN/Forms/GroupSettingForm.cs
index 77860153..80ae01b6 100644
--- a/v2rayN/v2rayN/Forms/GroupSettingForm.cs
+++ b/v2rayN/v2rayN/Forms/GroupSettingForm.cs
@@ -18,10 +18,7 @@ namespace v2rayN.Forms
 
         private void GroupSettingForm_Load(object sender, EventArgs e)
         {
-            if (config.groupItem == null)
-            {
-                config.groupItem = new List<GroupItem>();
-            }
+            config.groupItem ??= new List<GroupItem>();
 
             RefreshGroupsView();
         }
diff --git a/v2rayN/v2rayN/Forms/MainForm.cs b/v2rayN/v2rayN/Forms/MainForm.cs
index 59c8918b..cc36193a 100644
--- a/v2rayN/v2rayN/Forms/MainForm.cs
+++ b/v2rayN/v2rayN/Forms/MainForm.cs
@@ -63,14 +63,7 @@ namespace v2rayN.Forms
         private void MainForm_VisibleChanged(object sender, EventArgs e)
         {
             if (statistics == null || !statistics.Enable) return;
-            if ((sender as Form).Visible)
-            {
-                statistics.UpdateUI = true;
-            }
-            else
-            {
-                statistics.UpdateUI = false;
-            }
+            statistics.UpdateUI = (sender as Form).Visible;
         }
 
         private void MainForm_Shown(object sender, EventArgs e)
@@ -232,10 +225,7 @@ namespace v2rayN.Forms
                 .ToList();
 
             ConfigHandler.SetDefaultServer(config, lstVmess);
-            BeginInvoke(new Action(() =>
-            {
-                RefreshServersView();
-            }));
+            BeginInvoke(new Action(RefreshServersView));
 
             RefreshServersMenu();
         }
@@ -319,7 +309,7 @@ namespace v2rayN.Forms
                 Utils.AddSubItem(lvItem, EServerColName.subRemarks.ToString(), item.GetSubRemarks(config));
                 Utils.AddSubItem(lvItem, EServerColName.testResult.ToString(), item.testResult);
 
-                if (statistics != null && statistics.Enable)
+                if (statistics is { Enable: true })
                 {
                     string totalUp = string.Empty,
                         totalDown = string.Empty,
@@ -1048,10 +1038,7 @@ namespace v2rayN.Forms
         {
             HideForm();
 
-            string result = await Task.Run(() =>
-            {
-                return Utils.ScanScreen();
-            });
+            string result = await Task.Run(Utils.ScanScreen);
 
             ShowForm();
 
@@ -1234,7 +1221,7 @@ namespace v2rayN.Forms
             {
                 up /= (ulong)(config.statisticsFreshRate);
                 down /= (ulong)(config.statisticsFreshRate);
-                mainMsgControl.SetToolSslInfo("speed", string.Format("{0}/s↑ | {1}/s↓", Utils.HumanFy(up), Utils.HumanFy(down)));
+                mainMsgControl.SetToolSslInfo("speed", $"{Utils.HumanFy(up)}/s↑ | {Utils.HumanFy(down)}/s↓");
 
                 foreach (var it in statistics)
                 {
@@ -1560,7 +1547,7 @@ namespace v2rayN.Forms
             for (int k = 0; k < config.routings.Count; k++)
             {
                 var item = config.routings[k];
-                if (item.locked == true)
+                if (item.locked)
                 {
                     continue;
                 }
diff --git a/v2rayN/v2rayN/Forms/MainMsgControl.cs b/v2rayN/v2rayN/Forms/MainMsgControl.cs
index 6696573c..97ef7a68 100644
--- a/v2rayN/v2rayN/Forms/MainMsgControl.cs
+++ b/v2rayN/v2rayN/Forms/MainMsgControl.cs
@@ -1,12 +1,6 @@
 using System;
-using System.Collections.Generic;
-using System.ComponentModel;
-using System.Data;
-using System.Drawing;
-using System.Linq;
 using System.Text;
 using System.Text.RegularExpressions;
-using System.Threading.Tasks;
 using System.Windows.Forms;
 using v2rayN.Base;
 using v2rayN.Mode;
@@ -89,14 +83,9 @@ namespace v2rayN.Forms
             sb.Append($"{ResUI.LabLocal}:");
             sb.Append($"[{Global.InboundSocks}:{config.GetLocalPort(Global.InboundSocks)}]");
             sb.Append(" | ");
-            if (config.sysProxyType == ESysProxyType.ForcedChange)
-            {
-                sb.Append($"[{Global.InboundHttp}({ResUI.SystemProxy}):{config.GetLocalPort(Global.InboundHttp)}]");
-            }
-            else
-            {
-                sb.Append($"[{Global.InboundHttp}:{config.GetLocalPort(Global.InboundHttp)}]");
-            }
+            sb.Append(config.sysProxyType == ESysProxyType.ForcedChange
+                ? $"[{Global.InboundHttp}({ResUI.SystemProxy}):{config.GetLocalPort(Global.InboundHttp)}]"
+                : $"[{Global.InboundHttp}:{config.GetLocalPort(Global.InboundHttp)}]");
 
             if (config.inbound[0].allowLANConn)
             {
diff --git a/v2rayN/v2rayN/Forms/MsgFilterSetForm.cs b/v2rayN/v2rayN/Forms/MsgFilterSetForm.cs
index 926b00cb..01c4f773 100644
--- a/v2rayN/v2rayN/Forms/MsgFilterSetForm.cs
+++ b/v2rayN/v2rayN/Forms/MsgFilterSetForm.cs
@@ -1,11 +1,4 @@
 using System;
-using System.Collections.Generic;
-using System.ComponentModel;
-using System.Data;
-using System.Drawing;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 using System.Windows.Forms;
 
 namespace v2rayN.Forms
diff --git a/v2rayN/v2rayN/Forms/OptionSettingForm.cs b/v2rayN/v2rayN/Forms/OptionSettingForm.cs
index 4c357b83..98c0d1cb 100644
--- a/v2rayN/v2rayN/Forms/OptionSettingForm.cs
+++ b/v2rayN/v2rayN/Forms/OptionSettingForm.cs
@@ -106,10 +106,7 @@ namespace v2rayN.Forms
 
         private void InitCoreType()
         {
-            if (config.coreTypeItem == null)
-            {
-                config.coreTypeItem = new List<CoreTypeItem>();
-            }
+            config.coreTypeItem ??= new List<CoreTypeItem>();
 
             foreach (EConfigType it in Enum.GetValues(typeof(EConfigType)))
             {
diff --git a/v2rayN/v2rayN/Forms/RoutingRuleSettingDetailsForm.cs b/v2rayN/v2rayN/Forms/RoutingRuleSettingDetailsForm.cs
index fa600925..c02cccc1 100644
--- a/v2rayN/v2rayN/Forms/RoutingRuleSettingDetailsForm.cs
+++ b/v2rayN/v2rayN/Forms/RoutingRuleSettingDetailsForm.cs
@@ -3,7 +3,6 @@ using System.Collections.Generic;
 using System.Diagnostics;
 using System.Windows.Forms;
 using v2rayN.Base;
-using v2rayN.Handler;
 using v2rayN.Mode;
 using v2rayN.Resx;
 
@@ -117,13 +116,10 @@ namespace v2rayN.Forms
         {
             EndBindingData();
 
-            bool hasRule = 
-                rulesItem.domain != null 
-                && rulesItem.domain.Count > 0 
-                || rulesItem.ip != null 
-                && rulesItem.ip.Count > 0 
-                || rulesItem.protocol != null 
-                && rulesItem.protocol.Count > 0 
+            bool hasRule =
+                rulesItem.domain is { Count: > 0 }
+                || rulesItem.ip is { Count: > 0 }
+                || rulesItem.protocol is { Count: > 0 }
                 || !Utils.IsNullOrEmpty(rulesItem.port);
 
             if (!hasRule)
diff --git a/v2rayN/v2rayN/Forms/RoutingRuleSettingForm.cs b/v2rayN/v2rayN/Forms/RoutingRuleSettingForm.cs
index b88d67d1..54feb7f7 100644
--- a/v2rayN/v2rayN/Forms/RoutingRuleSettingForm.cs
+++ b/v2rayN/v2rayN/Forms/RoutingRuleSettingForm.cs
@@ -2,7 +2,6 @@
 using System.Collections.Generic;
 using System.Threading.Tasks;
 using System.Windows.Forms;
-using v2rayN.Base;
 using v2rayN.Handler;
 using v2rayN.Mode;
 using v2rayN.Resx;
@@ -26,10 +25,7 @@ namespace v2rayN.Forms
         private void RoutingRuleSettingForm_Load(object sender, EventArgs e)
         {
             routingItem = EditIndex >= 0 ? config.routings[EditIndex] : new RoutingItem();
-            if (routingItem.rules == null)
-            {
-                routingItem.rules = new List<RulesItem>();
-            }
+            routingItem.rules ??= new List<RulesItem>();
 
             txtRemarks.Text = routingItem.remarks ?? string.Empty;
             txtUrl.Text = routingItem.url ?? string.Empty;
@@ -351,11 +347,7 @@ namespace v2rayN.Forms
         }
         private int AddBatchRoutingRules(ref RoutingItem routingItem, string clipboardData)
         {
-            bool blReplace = false;
-            if (UI.ShowYesNo(ResUI.AddBatchRoutingRulesYesNo) == DialogResult.No)
-            {
-                blReplace = true;
-            }
+            bool blReplace = UI.ShowYesNo(ResUI.AddBatchRoutingRulesYesNo) == DialogResult.No;
             return ConfigHandler.AddBatchRoutingRules(ref routingItem, clipboardData, blReplace);
         }
 
diff --git a/v2rayN/v2rayN/Forms/RoutingSettingForm.cs b/v2rayN/v2rayN/Forms/RoutingSettingForm.cs
index a34b01d7..20fd55de 100644
--- a/v2rayN/v2rayN/Forms/RoutingSettingForm.cs
+++ b/v2rayN/v2rayN/Forms/RoutingSettingForm.cs
@@ -26,10 +26,7 @@ namespace v2rayN.Forms
             chkenableRoutingAdvanced.Checked = config.enableRoutingAdvanced;
             cmbdomainMatcher.Text = config.domainMatcher;
 
-            if (config.routings == null)
-            {
-                config.routings = new List<RoutingItem>();
-            }
+            config.routings ??= new List<RoutingItem>();
             InitRoutingsView();
             RefreshRoutingsView();
 
@@ -162,7 +159,7 @@ namespace v2rayN.Forms
             for (int k = 0; k < config.routings.Count; k++)
             {
                 var item = config.routings[k];
-                if (item.locked == true)
+                if (item.locked)
                 {
                     continue;
                 }
diff --git a/v2rayN/v2rayN/Forms/SubSettingControl.cs b/v2rayN/v2rayN/Forms/SubSettingControl.cs
index 12f8896c..8fc61226 100644
--- a/v2rayN/v2rayN/Forms/SubSettingControl.cs
+++ b/v2rayN/v2rayN/Forms/SubSettingControl.cs
@@ -62,14 +62,7 @@ namespace v2rayN.Forms
                 subItem.userAgent = txtUserAgent.Text.TrimEx();
 
                 var index = groupItem.FindIndex(t => t.remarks == cmbGroup.Text);
-                if (index >= 0)
-                {
-                    subItem.groupId = groupItem[index].id;
-                }
-                else
-                {
-                    subItem.groupId = string.Empty;
-                }
+                subItem.groupId = index >= 0 ? groupItem[index].id : string.Empty;
             }
         }
         private void txtRemarks_Leave(object sender, EventArgs e)
diff --git a/v2rayN/v2rayN/Forms/SubSettingForm.cs b/v2rayN/v2rayN/Forms/SubSettingForm.cs
index 1312c4a0..8eed6ba0 100644
--- a/v2rayN/v2rayN/Forms/SubSettingForm.cs
+++ b/v2rayN/v2rayN/Forms/SubSettingForm.cs
@@ -18,10 +18,7 @@ namespace v2rayN.Forms
 
         private void SubSettingForm_Load(object sender, EventArgs e)
         {
-            if (config.subItem == null)
-            {
-                config.subItem = new List<SubItem>();
-            }
+            config.subItem ??= new List<SubItem>();
 
             RefreshSubsView();
         }
diff --git a/v2rayN/v2rayN/Handler/ConfigHandler.cs b/v2rayN/v2rayN/Handler/ConfigHandler.cs
index 7fc1a687..f66e7505 100644
--- a/v2rayN/v2rayN/Handler/ConfigHandler.cs
+++ b/v2rayN/v2rayN/Handler/ConfigHandler.cs
@@ -1,12 +1,10 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Net;
 using v2rayN.Mode;
 using v2rayN.Base;
 using System.Linq;
 using v2rayN.Tool;
-using System.Threading.Tasks;
 
 namespace v2rayN.Handler
 {
@@ -101,36 +99,22 @@ namespace v2rayN.Handler
             //}
 
             //kcp
-            if (config.kcpItem == null)
+            config.kcpItem ??= new KcpItem
             {
-                config.kcpItem = new KcpItem
-                {
-                    mtu = 1350,
-                    tti = 50,
-                    uplinkCapacity = 12,
-                    downlinkCapacity = 100,
-                    readBufferSize = 2,
-                    writeBufferSize = 2,
-                    congestion = false
-                };
-            }
-            if (config.uiItem == null)
+                mtu = 1350,
+                tti = 50,
+                uplinkCapacity = 12,
+                downlinkCapacity = 100,
+                readBufferSize = 2,
+                writeBufferSize = 2,
+                congestion = false
+            };
+            config.uiItem ??= new UIItem()
             {
-                config.uiItem = new UIItem()
-                {
-                    enableAutoAdjustMainLvColWidth = true
-                };
-            }
-            if (config.uiItem.mainLvColWidth == null)
-            {
-                config.uiItem.mainLvColWidth = new Dictionary<string, int>();
-            }
-
-
-            if (config.constItem == null)
-            {
-                config.constItem = new ConstItem();
-            }
+                enableAutoAdjustMainLvColWidth = true
+            };
+            config.uiItem.mainLvColWidth ??= new Dictionary<string, int>();
+            config.constItem ??= new ConstItem();
             if (Utils.IsNullOrEmpty(config.constItem.speedTestUrl))
             {
                 config.constItem.speedTestUrl = Global.SpeedTestUrl;
@@ -148,15 +132,9 @@ namespace v2rayN.Handler
             //    config.remoteDNS = "1.1.1.1";
             //}
 
-            if (config.subItem == null)
-            {
-                config.subItem = new List<SubItem>();
-            }
-            if (config.groupItem == null)
-            {
-                config.groupItem = new List<GroupItem>();
-            }
-            if (config.statisticsFreshRate > 100 || config.statisticsFreshRate < 1)
+            config.subItem ??= new List<SubItem>();
+            config.groupItem ??= new List<GroupItem>();
+            if (config.statisticsFreshRate is > 100 or < 1)
             {
                 config.statisticsFreshRate = 1;
             }
@@ -1260,10 +1238,7 @@ namespace v2rayN.Handler
 
         public static int AddformMainLvColWidth(ref Config config, string name, int width)
         {
-            if (config.uiItem.mainLvColWidth == null)
-            {
-                config.uiItem.mainLvColWidth = new Dictionary<string, int>();
-            }
+            config.uiItem.mainLvColWidth ??= new Dictionary<string, int>();
             if (config.uiItem.mainLvColWidth.ContainsKey(name))
             {
                 config.uiItem.mainLvColWidth[name] = width;
@@ -1278,18 +1253,8 @@ namespace v2rayN.Handler
         }
         public static int GetformMainLvColWidth(ref Config config, string name, int width)
         {
-            if (config.uiItem.mainLvColWidth == null)
-            {
-                config.uiItem.mainLvColWidth = new Dictionary<string, int>();
-            }
-            if (config.uiItem.mainLvColWidth.ContainsKey(name))
-            {
-                return config.uiItem.mainLvColWidth[name];
-            }
-            else
-            {
-                return width;
-            }
+            config.uiItem.mainLvColWidth ??= new Dictionary<string, int>();
+            return config.uiItem.mainLvColWidth.ContainsKey(name) ? config.uiItem.mainLvColWidth[name] : width;
         }
 
         #endregion
@@ -1308,7 +1273,7 @@ namespace v2rayN.Handler
 
             }
             //move locked item
-            int index = config.routings.FindIndex(it => it.locked == true);
+            int index = config.routings.FindIndex(it => it.locked);
             if (index != -1)
             {
                 var item = Utils.DeepCopy(config.routings[index]);
@@ -1339,7 +1304,7 @@ namespace v2rayN.Handler
             else
             {
                 config.routings.Add(item);
-                int indexLocked = config.routings.FindIndex(it => it.locked == true);
+                int indexLocked = config.routings.FindIndex(it => it.locked);
                 if (indexLocked != -1)
                 {
                     var itemLocked = Utils.DeepCopy(config.routings[indexLocked]);
@@ -1370,10 +1335,7 @@ namespace v2rayN.Handler
             {
                 return -1;
             }
-            if (routingItem.rules == null)
-            {
-                routingItem.rules = new List<RulesItem>();
-            }
+            routingItem.rules ??= new List<RulesItem>();
             if (blReplace)
             {
                 routingItem.rules.Clear();
@@ -1485,10 +1447,7 @@ namespace v2rayN.Handler
 
         public static int InitBuiltinRouting(ref Config config, bool blImportAdvancedRules = false)
         {
-            if (config.routings == null)
-            {
-                config.routings = new List<RoutingItem>();
-            }
+            config.routings ??= new List<RoutingItem>();
 
             if (blImportAdvancedRules || config.routings.Count(it => it.locked != true) <= 0)
             {
@@ -1543,11 +1502,7 @@ namespace v2rayN.Handler
 
         public static RoutingItem GetLockedRoutingItem(ref Config config)
         {
-            if (config.routings == null)
-            {
-                return null;
-            }
-            return config.routings.Find(it => it.locked == true);
+            return config.routings?.Find(it => it.locked);
         }
         #endregion
     }
diff --git a/v2rayN/v2rayN/Handler/DownloadHandle.cs b/v2rayN/v2rayN/Handler/DownloadHandle.cs
index 5d4d3caf..86fdc3cc 100644
--- a/v2rayN/v2rayN/Handler/DownloadHandle.cs
+++ b/v2rayN/v2rayN/Handler/DownloadHandle.cs
@@ -5,7 +5,6 @@ using System.Net;
 using System.Net.Http;
 using System.Net.Http.Headers;
 using System.Net.Sockets;
-using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using v2rayN.Base;
diff --git a/v2rayN/v2rayN/Handler/LazyConfig.cs b/v2rayN/v2rayN/Handler/LazyConfig.cs
index 2a89f526..f4d21e4d 100644
--- a/v2rayN/v2rayN/Handler/LazyConfig.cs
+++ b/v2rayN/v2rayN/Handler/LazyConfig.cs
@@ -48,11 +48,7 @@ namespace v2rayN.Handler
                 return ECoreType.Xray;
             }
             var item = _config.coreTypeItem.FirstOrDefault(it => it.configType == eConfigType);
-            if (item == null)
-            {
-                return ECoreType.Xray;
-            }
-            return item.coreType;
+            return item?.coreType ?? ECoreType.Xray;
         }
 
         public CoreInfo GetCoreInfo(ECoreType coreType)
@@ -61,144 +57,135 @@ namespace v2rayN.Handler
             {
                 InitCoreInfo();
             }
-            return coreInfos.Where(t => t.coreType == coreType).FirstOrDefault();
+            return coreInfos.FirstOrDefault(t => t.coreType == coreType);
         }
 
         private void InitCoreInfo()
         {
-            coreInfos = new List<CoreInfo>();
-
-            coreInfos.Add(new CoreInfo
+            coreInfos = new List<CoreInfo>
             {
-                coreType = ECoreType.v2rayN,
-                coreUrl = Global.NUrl,
-                coreReleaseApiUrl = Global.NUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
-                coreDownloadUrl32 = Global.NUrl + "/download/{0}/v2rayN.zip",
-                coreDownloadUrl64 = Global.NUrl + "/download/{0}/v2rayN.zip",
-            });
-
-            coreInfos.Add(new CoreInfo
-            {
-                coreType = ECoreType.v2fly,
-                coreExes = new List<string> { "wv2ray", "v2ray" },
-                arguments = "",
-                coreUrl = Global.v2flyCoreUrl,
-                coreReleaseApiUrl = Global.v2flyCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
-                coreDownloadUrl32 = Global.v2flyCoreUrl + "/download/{0}/v2ray-windows-{1}.zip",
-                coreDownloadUrl64 = Global.v2flyCoreUrl + "/download/{0}/v2ray-windows-{1}.zip",
-                match = "V2Ray",
-                versionArg = "-version",
-                redirectInfo = true,
-            });
-
-            coreInfos.Add(new CoreInfo
-            {
-                coreType = ECoreType.SagerNet,
-                coreExes = new List<string> { "SagerNet", "v2ray" },
-                arguments = "run",
-                coreUrl = Global.SagerNetCoreUrl,
-                coreReleaseApiUrl = Global.SagerNetCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
-                coreDownloadUrl32 = Global.SagerNetCoreUrl + "/download/{0}/v2ray-windows-{1}.zip",
-                coreDownloadUrl64 = Global.SagerNetCoreUrl + "/download/{0}/v2ray-windows-{1}.zip",
-                match = "V2Ray",
-                versionArg = "version",
-                redirectInfo = true,
-            });
-
-            coreInfos.Add(new CoreInfo
-            {
-                coreType = ECoreType.v2fly_v5,
-                coreExes = new List<string> { "v2ray" },
-                arguments = "run",
-                coreUrl = Global.v2flyCoreUrl,
-                coreReleaseApiUrl = Global.v2flyCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
-                coreDownloadUrl32 = Global.v2flyCoreUrl + "/download/{0}/v2ray-windows-{1}.zip",
-                coreDownloadUrl64 = Global.v2flyCoreUrl + "/download/{0}/v2ray-windows-{1}.zip",
-                match = "V2Ray",
-                versionArg = "version",
-                redirectInfo = true,
-            });
-
-            coreInfos.Add(new CoreInfo
-            {
-                coreType = ECoreType.Xray,
-                coreExes = new List<string> { "xray" },
-                arguments = "",
-                coreUrl = Global.xrayCoreUrl,
-                coreReleaseApiUrl = Global.xrayCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
-                coreDownloadUrl32 = Global.xrayCoreUrl + "/download/{0}/Xray-windows-{1}.zip",
-                coreDownloadUrl64 = Global.xrayCoreUrl + "/download/{0}/Xray-windows-{1}.zip",
-                match = "Xray",
-                versionArg = "-version",
-                redirectInfo = true,
-            });
-
-            coreInfos.Add(new CoreInfo
-            {
-                coreType = ECoreType.clash,
-                coreExes = new List<string> { "clash-windows-amd64-v3", "clash-windows-amd64", "clash-windows-386", "clash" },
-                arguments = "-f config.json",
-                coreUrl = Global.clashCoreUrl,
-                coreReleaseApiUrl = Global.clashCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
-                coreDownloadUrl32 = Global.clashCoreUrl + "/download/{0}/clash-windows-386-{0}.zip",
-                coreDownloadUrl64 = Global.clashCoreUrl + "/download/{0}/clash-windows-amd64-{0}.zip",
-                match = "v",
-                versionArg = "-v",
-                redirectInfo = true,
-            });
-
-            coreInfos.Add(new CoreInfo
-            {
-                coreType = ECoreType.clash_meta,
-                coreExes = new List<string> { "Clash.Meta-windows-amd64-compatible", "Clash.Meta-windows-amd64", "Clash.Meta-windows-386", "Clash.Meta", "clash" },
-                arguments = "-f config.json",
-                coreUrl = Global.clashMetaCoreUrl,
-                coreReleaseApiUrl = Global.clashMetaCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
-                coreDownloadUrl32 = Global.clashMetaCoreUrl + "/download/{0}/Clash.Meta-windows-386-{0}.zip",
-                coreDownloadUrl64 = Global.clashMetaCoreUrl + "/download/{0}/Clash.Meta-windows-amd64-compatible-{0}.zip",
-                match = "v",
-                versionArg = "-v",
-                redirectInfo = true,
-            });
-
-            coreInfos.Add(new CoreInfo
-            {
-                coreType = ECoreType.hysteria,
-                coreExes = new List<string> { "hysteria-windows-amd64", "hysteria-windows-386", "hysteria" },
-                arguments = "",
-                coreUrl = Global.hysteriaCoreUrl,
-                coreReleaseApiUrl = Global.hysteriaCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
-                coreDownloadUrl32 = Global.hysteriaCoreUrl + "/download/{0}/hysteria-windows-386.exe",
-                coreDownloadUrl64 = Global.hysteriaCoreUrl + "/download/{0}/hysteria-windows-amd64.exe",
-                redirectInfo = true,
-            });
-
-            coreInfos.Add(new CoreInfo
-            {
-                coreType = ECoreType.naiveproxy,
-                coreExes = new List<string> { "naiveproxy", "naive" },
-                arguments = "config.json",
-                coreUrl = Global.naiveproxyCoreUrl,
-                redirectInfo = false,
-            });
-
-            coreInfos.Add(new CoreInfo
-            {
-                coreType = ECoreType.tuic,
-                coreExes = new List<string> { "tuic-client", "tuic" },
-                arguments = "-c config.json",
-                coreUrl = Global.tuicCoreUrl,
-                redirectInfo = true,
-            });
-
-            coreInfos.Add(new CoreInfo
-            {
-                coreType = ECoreType.sing_box,
-                coreExes = new List<string> { "sing-box-client", "sing-box" },
-                arguments = "run",
-                coreUrl = Global.singboxCoreUrl,
-                redirectInfo = true,
-            });
+                new CoreInfo
+                {
+                    coreType = ECoreType.v2rayN,
+                    coreUrl = Global.NUrl,
+                    coreReleaseApiUrl = Global.NUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
+                    coreDownloadUrl32 = Global.NUrl + "/download/{0}/v2rayN.zip",
+                    coreDownloadUrl64 = Global.NUrl + "/download/{0}/v2rayN.zip",
+                },
+                new CoreInfo
+                {
+                    coreType = ECoreType.v2fly,
+                    coreExes = new List<string> { "wv2ray", "v2ray" },
+                    arguments = "",
+                    coreUrl = Global.v2flyCoreUrl,
+                    coreReleaseApiUrl = Global.v2flyCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
+                    coreDownloadUrl32 = Global.v2flyCoreUrl + "/download/{0}/v2ray-windows-{1}.zip",
+                    coreDownloadUrl64 = Global.v2flyCoreUrl + "/download/{0}/v2ray-windows-{1}.zip",
+                    match = "V2Ray",
+                    versionArg = "-version",
+                    redirectInfo = true,
+                },
+                new CoreInfo
+                {
+                    coreType = ECoreType.SagerNet,
+                    coreExes = new List<string> { "SagerNet", "v2ray" },
+                    arguments = "run",
+                    coreUrl = Global.SagerNetCoreUrl,
+                    coreReleaseApiUrl = Global.SagerNetCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
+                    coreDownloadUrl32 = Global.SagerNetCoreUrl + "/download/{0}/v2ray-windows-{1}.zip",
+                    coreDownloadUrl64 = Global.SagerNetCoreUrl + "/download/{0}/v2ray-windows-{1}.zip",
+                    match = "V2Ray",
+                    versionArg = "version",
+                    redirectInfo = true,
+                },
+                new CoreInfo
+                {
+                    coreType = ECoreType.v2fly_v5,
+                    coreExes = new List<string> { "v2ray" },
+                    arguments = "run",
+                    coreUrl = Global.v2flyCoreUrl,
+                    coreReleaseApiUrl = Global.v2flyCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
+                    coreDownloadUrl32 = Global.v2flyCoreUrl + "/download/{0}/v2ray-windows-{1}.zip",
+                    coreDownloadUrl64 = Global.v2flyCoreUrl + "/download/{0}/v2ray-windows-{1}.zip",
+                    match = "V2Ray",
+                    versionArg = "version",
+                    redirectInfo = true,
+                },
+                new CoreInfo
+                {
+                    coreType = ECoreType.Xray,
+                    coreExes = new List<string> { "xray" },
+                    arguments = "",
+                    coreUrl = Global.xrayCoreUrl,
+                    coreReleaseApiUrl = Global.xrayCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
+                    coreDownloadUrl32 = Global.xrayCoreUrl + "/download/{0}/Xray-windows-{1}.zip",
+                    coreDownloadUrl64 = Global.xrayCoreUrl + "/download/{0}/Xray-windows-{1}.zip",
+                    match = "Xray",
+                    versionArg = "-version",
+                    redirectInfo = true,
+                },
+                new CoreInfo
+                {
+                    coreType = ECoreType.clash,
+                    coreExes = new List<string> { "clash-windows-amd64-v3", "clash-windows-amd64", "clash-windows-386", "clash" },
+                    arguments = "-f config.json",
+                    coreUrl = Global.clashCoreUrl,
+                    coreReleaseApiUrl = Global.clashCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
+                    coreDownloadUrl32 = Global.clashCoreUrl + "/download/{0}/clash-windows-386-{0}.zip",
+                    coreDownloadUrl64 = Global.clashCoreUrl + "/download/{0}/clash-windows-amd64-{0}.zip",
+                    match = "v",
+                    versionArg = "-v",
+                    redirectInfo = true,
+                },
+                new CoreInfo
+                {
+                    coreType = ECoreType.clash_meta,
+                    coreExes = new List<string> { "Clash.Meta-windows-amd64-compatible", "Clash.Meta-windows-amd64", "Clash.Meta-windows-386", "Clash.Meta", "clash" },
+                    arguments = "-f config.json",
+                    coreUrl = Global.clashMetaCoreUrl,
+                    coreReleaseApiUrl = Global.clashMetaCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
+                    coreDownloadUrl32 = Global.clashMetaCoreUrl + "/download/{0}/Clash.Meta-windows-386-{0}.zip",
+                    coreDownloadUrl64 = Global.clashMetaCoreUrl + "/download/{0}/Clash.Meta-windows-amd64-compatible-{0}.zip",
+                    match = "v",
+                    versionArg = "-v",
+                    redirectInfo = true,
+                },
+                new CoreInfo
+                {
+                    coreType = ECoreType.hysteria,
+                    coreExes = new List<string> { "hysteria-windows-amd64", "hysteria-windows-386", "hysteria" },
+                    arguments = "",
+                    coreUrl = Global.hysteriaCoreUrl,
+                    coreReleaseApiUrl = Global.hysteriaCoreUrl.Replace(@"https://github.com", @"https://api.github.com/repos"),
+                    coreDownloadUrl32 = Global.hysteriaCoreUrl + "/download/{0}/hysteria-windows-386.exe",
+                    coreDownloadUrl64 = Global.hysteriaCoreUrl + "/download/{0}/hysteria-windows-amd64.exe",
+                    redirectInfo = true,
+                },
+                new CoreInfo
+                {
+                    coreType = ECoreType.naiveproxy,
+                    coreExes = new List<string> { "naiveproxy", "naive" },
+                    arguments = "config.json",
+                    coreUrl = Global.naiveproxyCoreUrl,
+                    redirectInfo = false,
+                },
+                new CoreInfo
+                {
+                    coreType = ECoreType.tuic,
+                    coreExes = new List<string> { "tuic-client", "tuic" },
+                    arguments = "-c config.json",
+                    coreUrl = Global.tuicCoreUrl,
+                    redirectInfo = true,
+                },
+                new CoreInfo
+                {
+                    coreType = ECoreType.sing_box,
+                    coreExes = new List<string> { "sing-box-client", "sing-box" },
+                    arguments = "run",
+                    coreUrl = Global.singboxCoreUrl,
+                    redirectInfo = true,
+                }
+            };
         }
 
     }
diff --git a/v2rayN/v2rayN/Handler/MainFormHandler.cs b/v2rayN/v2rayN/Handler/MainFormHandler.cs
index 240d04ff..7327395e 100644
--- a/v2rayN/v2rayN/Handler/MainFormHandler.cs
+++ b/v2rayN/v2rayN/Handler/MainFormHandler.cs
@@ -1,14 +1,12 @@
 using NHotkey;
 using NHotkey.WindowsForms;
 using System;
-using System.Collections.Generic;
 using System.Drawing;
 using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Windows.Forms;
 using v2rayN.Mode;
-using System.Linq;
 using v2rayN.Resx;
 
 namespace v2rayN.Handler
diff --git a/v2rayN/v2rayN/Handler/ShareHandler.cs b/v2rayN/v2rayN/Handler/ShareHandler.cs
index 55a40eac..31870685 100644
--- a/v2rayN/v2rayN/Handler/ShareHandler.cs
+++ b/v2rayN/v2rayN/Handler/ShareHandler.cs
@@ -2,10 +2,7 @@
 using System.Collections.Generic;
 using System.Collections.Specialized;
 using System.Linq;
-using System.Net;
-using System.Text;
 using System.Text.RegularExpressions;
-using System.Threading.Tasks;
 using System.Web;
 using v2rayN.Base;
 using v2rayN.Mode;
@@ -104,7 +101,7 @@ namespace v2rayN.Handler
             //url = Utils.Base64Encode(url);
             //new Sip002
             var pw = Utils.Base64Encode($"{item.security}:{item.id}");
-            url = $"{pw}@{GetIpv6(item.address)}:{ item.port}";
+            url = $"{pw}@{GetIpv6(item.address)}:{item.port}";
             url = $"{Global.ssProtocol}{url}{remark}";
             return url;
         }
@@ -125,7 +122,7 @@ namespace v2rayN.Handler
             //url = Utils.Base64Encode(url);
             //new
             var pw = Utils.Base64Encode($"{item.security}:{item.id}");
-            url = $"{pw}@{GetIpv6(item.address)}:{ item.port}";
+            url = $"{pw}@{GetIpv6(item.address)}:{item.port}";
             url = $"{Global.socksProtocol}{url}{remark}";
             return url;
         }
@@ -142,10 +139,7 @@ namespace v2rayN.Handler
             GetStdTransport(item, null, ref dicQuery);
             string query = "?" + string.Join("&", dicQuery.Select(x => x.Key + "=" + x.Value).ToArray());
 
-            url = string.Format("{0}@{1}:{2}",
-            item.id,
-            GetIpv6(item.address),
-            item.port);
+            url = $"{item.id}@{GetIpv6(item.address)}:{item.port}";
             url = $"{Global.trojanProtocol}{url}{query}{remark}";
             return url;
         }
@@ -158,22 +152,14 @@ namespace v2rayN.Handler
             {
                 remark = "#" + Utils.UrlEncode(item.remarks);
             }
-            var dicQuery = new Dictionary<string, string>();
-            if (!Utils.IsNullOrEmpty(item.security))
+            var dicQuery = new Dictionary<string, string>
             {
-                dicQuery.Add("encryption", item.security);
-            }
-            else
-            {
-                dicQuery.Add("encryption", "none");
-            }
+                { "encryption", !Utils.IsNullOrEmpty(item.security) ? item.security : "none" }
+            };
             GetStdTransport(item, "none", ref dicQuery);
             string query = "?" + string.Join("&", dicQuery.Select(x => x.Key + "=" + x.Value).ToArray());
 
-            url = string.Format("{0}@{1}:{2}",
-            item.id,
-            GetIpv6(item.address),
-            item.port);
+            url = $"{item.id}@{GetIpv6(item.address)}:{item.port}";
             url = $"{Global.vlessProtocol}{url}{query}{remark}";
             return url;
         }
@@ -204,7 +190,7 @@ namespace v2rayN.Handler
             {
                 dicQuery.Add("sni", item.sni);
             }
-            if (item.alpn != null && item.alpn.Count > 0)
+            if (item.alpn is { Count: > 0 })
             {
                 dicQuery.Add("alpn", Utils.UrlEncode(Utils.List2String(item.alpn)));
             }
@@ -261,7 +247,7 @@ namespace v2rayN.Handler
                     if (!Utils.IsNullOrEmpty(item.path))
                     {
                         dicQuery.Add("serviceName", Utils.UrlEncode(item.path));
-                        if (item.headerType == Global.GrpcgunMode || item.headerType == Global.GrpcmultiMode)
+                        if (item.headerType is Global.GrpcgunMode or Global.GrpcmultiMode)
                         {
                             dicQuery.Add("mode", Utils.UrlEncode(item.headerType));
                         }
diff --git a/v2rayN/v2rayN/Handler/SpeedtestHandler.cs b/v2rayN/v2rayN/Handler/SpeedtestHandler.cs
index e5d6022d..a9f6e2b1 100644
--- a/v2rayN/v2rayN/Handler/SpeedtestHandler.cs
+++ b/v2rayN/v2rayN/Handler/SpeedtestHandler.cs
@@ -13,10 +13,10 @@ namespace v2rayN.Handler
 {
     class SpeedtestHandler
     {
-        private Config _config;
-        private V2rayHandler _v2rayHandler;
-        private List<ServerTestItem> _selecteds;
-        Action<string, string> _updateFunc;
+        private readonly Config _config;
+        private readonly V2rayHandler _v2rayHandler;
+        private readonly List<ServerTestItem> _selecteds;
+        private readonly Action<string, string> _updateFunc;
 
         public SpeedtestHandler(Config config)
         {
@@ -137,8 +137,7 @@ namespace v2rayN.Handler
                         try
                         {
                             WebProxy webProxy = new WebProxy(Global.Loopback, it.port);
-                            int responseTime = -1;
-                            string status = downloadHandle.GetRealPingTime(_config.constItem.speedPingTestUrl, webProxy, out responseTime);
+                            string status = downloadHandle.GetRealPingTime(_config.constItem.speedPingTestUrl, webProxy, out var responseTime);
                             string output = Utils.IsNullOrEmpty(status) ? FormatOut(responseTime, "ms") : status;
 
                             _config.GetVmessItem(it.indexId)?.SetTestResult(output);
diff --git a/v2rayN/v2rayN/Handler/StatisticsHandler.cs b/v2rayN/v2rayN/Handler/StatisticsHandler.cs
index 65b6e687..f8fb70ba 100644
--- a/v2rayN/v2rayN/Handler/StatisticsHandler.cs
+++ b/v2rayN/v2rayN/Handler/StatisticsHandler.cs
@@ -1,6 +1,7 @@
 using Grpc.Core;
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Net;
 using System.Net.Sockets;
 using System.Threading;
@@ -149,24 +150,15 @@ namespace v2rayN.Handler
                     serverStatistics_ = Utils.FromJson<ServerStatistics>(result);
                 }
 
-                if (serverStatistics_ == null)
-                {
-                    serverStatistics_ = new ServerStatistics();
-                }
-                if (serverStatistics_.server == null)
-                {
-                    serverStatistics_.server = new List<ServerStatItem>();
-                }
+                serverStatistics_ ??= new ServerStatistics();
+                serverStatistics_.server ??= new List<ServerStatItem>();
 
                 long ticks = DateTime.Now.Date.Ticks;
-                foreach (ServerStatItem item in serverStatistics_.server)
+                foreach (var item in serverStatistics_.server.Where(item => item.dateNow != ticks))
                 {
-                    if (item.dateNow != ticks)
-                    {
-                        item.todayUp = 0;
-                        item.todayDown = 0;
-                        item.dateNow = ticks;
-                    }
+                    item.todayUp = 0;
+                    item.todayDown = 0;
+                    item.dateNow = ticks;
                 }
             }
             catch (Exception ex)
diff --git a/v2rayN/v2rayN/Handler/SysProxyHandle.cs b/v2rayN/v2rayN/Handler/SysProxyHandle.cs
index 815580ae..edd7a977 100644
--- a/v2rayN/v2rayN/Handler/SysProxyHandle.cs
+++ b/v2rayN/v2rayN/Handler/SysProxyHandle.cs
@@ -144,85 +144,81 @@ namespace v2rayN.Handler
             // using event to avoid hanging when redirect standard output/error
             // ref: https://stackoverflow.com/questions/139593/processstartinfo-hanging-on-waitforexit-why
             // and http://blog.csdn.net/zhangweixing0/article/details/7356841
-            using (AutoResetEvent outputWaitHandle = new AutoResetEvent(false))
-            using (AutoResetEvent errorWaitHandle = new AutoResetEvent(false))
+            using AutoResetEvent outputWaitHandle = new AutoResetEvent(false);
+            using AutoResetEvent errorWaitHandle = new AutoResetEvent(false);
+            using Process process = new Process();
+            // Configure the process using the StartInfo properties.
+            process.StartInfo.FileName = Utils.GetTempPath("sysproxy.exe");
+            process.StartInfo.Arguments = arguments;
+            process.StartInfo.WorkingDirectory = Utils.GetTempPath();
+            process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
+            process.StartInfo.UseShellExecute = false;
+            process.StartInfo.RedirectStandardError = true;
+            process.StartInfo.RedirectStandardOutput = true;
+
+            // Need to provide encoding info, or output/error strings we got will be wrong.
+            process.StartInfo.StandardOutputEncoding = Encoding.Unicode;
+            process.StartInfo.StandardErrorEncoding = Encoding.Unicode;
+
+            process.StartInfo.CreateNoWindow = true;
+
+            StringBuilder output = new StringBuilder();
+            StringBuilder error = new StringBuilder();
+
+            process.OutputDataReceived += (sender, e) =>
             {
-                using (Process process = new Process())
+                if (e.Data == null)
                 {
-                    // Configure the process using the StartInfo properties.
-                    process.StartInfo.FileName = Utils.GetTempPath("sysproxy.exe");
-                    process.StartInfo.Arguments = arguments;
-                    process.StartInfo.WorkingDirectory = Utils.GetTempPath();
-                    process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
-                    process.StartInfo.UseShellExecute = false;
-                    process.StartInfo.RedirectStandardError = true;
-                    process.StartInfo.RedirectStandardOutput = true;
-
-                    // Need to provide encoding info, or output/error strings we got will be wrong.
-                    process.StartInfo.StandardOutputEncoding = Encoding.Unicode;
-                    process.StartInfo.StandardErrorEncoding = Encoding.Unicode;
-
-                    process.StartInfo.CreateNoWindow = true;
-
-                    StringBuilder output = new StringBuilder();
-                    StringBuilder error = new StringBuilder();
-
-                    process.OutputDataReceived += (sender, e) =>
-                    {
-                        if (e.Data == null)
-                        {
-                            outputWaitHandle.Set();
-                        }
-                        else
-                        {
-                            output.AppendLine(e.Data);
-                        }
-                    };
-                    process.ErrorDataReceived += (sender, e) =>
-                    {
-                        if (e.Data == null)
-                        {
-                            errorWaitHandle.Set();
-                        }
-                        else
-                        {
-                            error.AppendLine(e.Data);
-                        }
-                    };
-                    try
-                    {
-                        process.Start();
-
-                        process.BeginErrorReadLine();
-                        process.BeginOutputReadLine();
-
-                        process.WaitForExit();
-                    }
-                    catch (System.ComponentModel.Win32Exception e)
-                    {
-
-                        // log the arguments
-                        throw new Exception(process.StartInfo.Arguments);
-                    }
-                    string stderr = error.ToString();
-                    string stdout = output.ToString();
-
-                    int exitCode = process.ExitCode;
-                    if (exitCode != (int)RET_ERRORS.RET_NO_ERROR)
-                    {
-                        throw new Exception(stderr);
-                    }
-
-                    //if (arguments == "query")
-                    //{
-                    //    if (stdout.IsNullOrWhiteSpace() || stdout.IsNullOrEmpty())
-                    //    {
-                    //        throw new Exception("failed to query wininet settings");
-                    //    }
-                    //    _queryStr = stdout;
-                    //}
+                    outputWaitHandle.Set();
                 }
+                else
+                {
+                    output.AppendLine(e.Data);
+                }
+            };
+            process.ErrorDataReceived += (sender, e) =>
+            {
+                if (e.Data == null)
+                {
+                    errorWaitHandle.Set();
+                }
+                else
+                {
+                    error.AppendLine(e.Data);
+                }
+            };
+            try
+            {
+                process.Start();
+
+                process.BeginErrorReadLine();
+                process.BeginOutputReadLine();
+
+                process.WaitForExit();
             }
+            catch (System.ComponentModel.Win32Exception e)
+            {
+
+                // log the arguments
+                throw new Exception(process.StartInfo.Arguments);
+            }
+            string stderr = error.ToString();
+            string stdout = output.ToString();
+
+            int exitCode = process.ExitCode;
+            if (exitCode != (int)RET_ERRORS.RET_NO_ERROR)
+            {
+                throw new Exception(stderr);
+            }
+
+            //if (arguments == "query")
+            //{
+            //    if (stdout.IsNullOrWhiteSpace() || stdout.IsNullOrEmpty())
+            //    {
+            //        throw new Exception("failed to query wininet settings");
+            //    }
+            //    _queryStr = stdout;
+            //}
         }
 
 
diff --git a/v2rayN/v2rayN/Handler/UpdateHandle.cs b/v2rayN/v2rayN/Handler/UpdateHandle.cs
index a6468fc9..69930a4d 100644
--- a/v2rayN/v2rayN/Handler/UpdateHandle.cs
+++ b/v2rayN/v2rayN/Handler/UpdateHandle.cs
@@ -8,7 +8,6 @@ using System.Text.RegularExpressions;
 using System.Threading;
 using System.Threading.Tasks;
 using System.Windows.Forms;
-using Newtonsoft.Json;
 using v2rayN.Base;
 using v2rayN.Mode;
 using v2rayN.Resx;
@@ -405,15 +404,7 @@ namespace v2rayN.Handler
             try
             {
                 var gitHubReleases = Utils.FromJson<List<GitHubRelease>>(gitHubReleaseApi);
-                string version;
-                if (preRelease)
-                {
-                    version = gitHubReleases!.First().TagName;
-                }
-                else
-                {
-                    version = gitHubReleases!.First(r => r.Prerelease == false).TagName;
-                }
+                var version = preRelease ? gitHubReleases!.First().TagName : gitHubReleases!.First(r => r.Prerelease == false).TagName;
                 var coreInfo = LazyConfig.Instance.GetCoreInfo(type);
 
                 string curVersion;
@@ -437,14 +428,9 @@ namespace v2rayN.Handler
                         {
                             curVersion = getCoreVersion(type);
                             message = string.Format(ResUI.IsLatestCore, curVersion);
-                            if (Environment.Is64BitProcess)
-                            {
-                                url = string.Format(coreInfo.coreDownloadUrl64, version);
-                            }
-                            else
-                            {
-                                url = string.Format(coreInfo.coreDownloadUrl32, version);
-                            }
+                            url = string.Format(Environment.Is64BitProcess 
+                                ? coreInfo.coreDownloadUrl64 
+                                : coreInfo.coreDownloadUrl32, version);
                             break;
                         }
                     case ECoreType.v2rayN:
diff --git a/v2rayN/v2rayN/Handler/V2rayConfigHandler.cs b/v2rayN/v2rayN/Handler/V2rayConfigHandler.cs
index 5e76f664..06603b95 100644
--- a/v2rayN/v2rayN/Handler/V2rayConfigHandler.cs
+++ b/v2rayN/v2rayN/Handler/V2rayConfigHandler.cs
@@ -246,21 +246,21 @@ namespace v2rayN.Handler
                 {
                     rules.port = null;
                 }
-                if (rules.domain != null && rules.domain.Count == 0)
+                if (rules.domain is { Count: 0 })
                 {
                     rules.domain = null;
                 }
-                if (rules.ip != null && rules.ip.Count == 0)
+                if (rules.ip is { Count: 0 })
                 {
                     rules.ip = null;
                 }
-                if (rules.protocol != null && rules.protocol.Count == 0)
+                if (rules.protocol is { Count: 0 })
                 {
                     rules.protocol = null;
                 }
 
                 var hasDomainIp = false;
-                if (rules.domain != null && rules.domain.Count > 0)
+                if (rules.domain is { Count: > 0 })
                 {
                     var it = Utils.DeepCopy(rules);
                     it.ip = null;
@@ -284,7 +284,7 @@ namespace v2rayN.Handler
                     v2rayConfig.routing.rules.Add(it);
                     hasDomainIp = true;
                 }
-                if (rules.ip != null && rules.ip.Count > 0)
+                if (rules.ip is { Count: > 0 })
                 {
                     var it = Utils.DeepCopy(rules);
                     it.domain = null;
@@ -314,7 +314,7 @@ namespace v2rayN.Handler
                         it.type = "field";
                         v2rayConfig.routing.rules.Add(it);
                     }
-                    else if (rules.protocol != null && rules.protocol.Count > 0)
+                    else if (rules.protocol is { Count: > 0 })
                     {
                         var it = Utils.DeepCopy(rules);
                         //it.domain = null;
@@ -377,14 +377,7 @@ namespace v2rayN.Handler
                     usersItem.id = node.id;
                     usersItem.alterId = node.alterId;
                     usersItem.email = Global.userEMail;
-                    if (Global.vmessSecuritys.Contains(node.security))
-                    {
-                        usersItem.security = node.security;
-                    }
-                    else
-                    {
-                        usersItem.security = Global.DefaultSecurity;
-                    }
+                    usersItem.security = Global.vmessSecuritys.Contains(node.security) ? node.security : Global.DefaultSecurity;
 
                     //Mux
                     outbound.mux.enabled = config.muxEnabled;
@@ -503,14 +496,7 @@ namespace v2rayN.Handler
                     //if xtls
                     if (node.streamSecurity == Global.StreamSecurityX)
                     {
-                        if (Utils.IsNullOrEmpty(node.flow))
-                        {
-                            usersItem.flow = Global.xtlsFlows[1];
-                        }
-                        else
-                        {
-                            usersItem.flow = node.flow.Replace("splice", "direct");
-                        }
+                        usersItem.flow = Utils.IsNullOrEmpty(node.flow) ? Global.xtlsFlows[1] : node.flow.Replace("splice", "direct");
 
                         outbound.mux.enabled = false;
                         outbound.mux.concurrency = -1;
@@ -553,14 +539,9 @@ namespace v2rayN.Handler
                     //if xtls
                     if (node.streamSecurity == Global.StreamSecurityX)
                     {
-                        if (Utils.IsNullOrEmpty(node.flow))
-                        {
-                            serversItem.flow = Global.xtlsFlows[1];
-                        }
-                        else
-                        {
-                            serversItem.flow = node.flow.Replace("splice", "direct");
-                        }
+                        serversItem.flow = Utils.IsNullOrEmpty(node.flow)
+                            ? Global.xtlsFlows[1]
+                            : node.flow.Replace("splice", "direct");
 
                         outbound.mux.enabled = false;
                         outbound.mux.concurrency = -1;
@@ -660,7 +641,7 @@ namespace v2rayN.Handler
                         }
                         else if (iobound.Equals("in"))
                         {
-                            kcpSettings.uplinkCapacity = config.kcpItem.downlinkCapacity; ;
+                            kcpSettings.uplinkCapacity = config.kcpItem.downlinkCapacity;
                             kcpSettings.downlinkCapacity = config.kcpItem.downlinkCapacity;
                         }
                         else
@@ -1423,10 +1404,6 @@ namespace v2rayN.Handler
                         if (!Utils.IsNullOrEmpty(request))
                         {
                             V2rayTcpRequest v2rayTcpRequest = Utils.FromJson<V2rayTcpRequest>(request);
-                            if (v2rayTcpRequest != null
-                                && v2rayTcpRequest.headers != null
-                                && v2rayTcpRequest.headers.Host != null
-                                && v2rayTcpRequest.headers.Host.Count > 0)
                             {
                                 vmessItem.requestHost = v2rayTcpRequest.headers.Host[0];
                             }
@@ -1465,17 +1442,14 @@ namespace v2rayN.Handler
                     {
                         vmessItem.path = inbound.streamSettings.httpSettings.path;
                     }
-                    if (inbound.streamSettings.httpSettings.host != null
-                        && inbound.streamSettings.httpSettings.host.Count > 0)
+                    if (inbound.streamSettings.httpSettings.host is { Count: > 0 })
                     {
                         vmessItem.requestHost = Utils.List2String(inbound.streamSettings.httpSettings.host);
                     }
                 }
 
                 //tls
-                if (inbound.streamSettings != null
-                    && inbound.streamSettings.security != null
-                    && inbound.streamSettings.security == Global.StreamSecurity)
+                if (inbound.streamSettings is { security: Global.StreamSecurity })
                 {
                     vmessItem.streamSecurity = Global.StreamSecurity;
                 }
diff --git a/v2rayN/v2rayN/Handler/V2rayHandler.cs b/v2rayN/v2rayN/Handler/V2rayHandler.cs
index 412bf95d..119376e6 100644
--- a/v2rayN/v2rayN/Handler/V2rayHandler.cs
+++ b/v2rayN/v2rayN/Handler/V2rayHandler.cs
@@ -63,7 +63,7 @@ namespace v2rayN.Handler
                 }
 
                 //start a socks service
-                if (_process != null && !_process.HasExited && item.configType == EConfigType.Custom && item.preSocksPort > 0)
+                if (_process is { HasExited: false } && item.configType == EConfigType.Custom && item.preSocksPort > 0)
                 {
                     var itemSocks = new VmessItem()
                     {
diff --git a/v2rayN/v2rayN/Mode/Config.cs b/v2rayN/v2rayN/Mode/Config.cs
index 6349b123..4430309d 100644
--- a/v2rayN/v2rayN/Mode/Config.cs
+++ b/v2rayN/v2rayN/Mode/Config.cs
@@ -275,11 +275,9 @@ namespace v2rayN.Mode
 
         public string GetGroupRemarks(string groupId)
         {
-            if (string.IsNullOrEmpty(groupId))
-            {
-                return string.Empty;
-            }
-            return groupItem.Where(it => it.id == groupId).FirstOrDefault()?.remarks;
+            return string.IsNullOrEmpty(groupId) 
+                ? string.Empty 
+                : groupItem.FirstOrDefault(it => it.id == groupId)?.remarks;
         }
 
         #endregion
@@ -316,21 +314,14 @@ namespace v2rayN.Mode
         #region function
         public string GetSummary()
         {
-            string summary = string.Format("[{0}] ", (configType).ToString());
+            string summary = $"[{(configType).ToString()}] ";
             string[] arrAddr = address.Split('.');
-            string addr;
-            if (arrAddr.Length > 2)
+            string addr = arrAddr.Length switch
             {
-                addr = $"{arrAddr[0]}***{arrAddr[arrAddr.Length - 1]}";
-            }
-            else if (arrAddr.Length > 1)
-            {
-                addr = $"***{arrAddr[arrAddr.Length - 1]}";
-            }
-            else
-            {
-                addr = address;
-            }
+                > 2 => $"{arrAddr[0]}***{arrAddr[arrAddr.Length - 1]}",
+                > 1 => $"***{arrAddr[arrAddr.Length - 1]}",
+                _ => address
+            };
             switch (configType)
             {
                 case EConfigType.VMess:
@@ -338,10 +329,10 @@ namespace v2rayN.Mode
                 case EConfigType.Socks:
                 case EConfigType.VLESS:
                 case EConfigType.Trojan:
-                    summary += string.Format("{0}({1}:{2})", remarks, addr, port);
+                    summary += $"{remarks}({addr}:{port})";
                     break;
                 default:
-                    summary += string.Format("{0}", remarks);
+                    summary += $"{remarks}";
                     break;
             }
             return summary;
@@ -372,23 +363,12 @@ namespace v2rayN.Mode
                 return subRemarks;
             }
             var group = config.groupItem.FirstOrDefault(t => t.id == groupId);
-            if (group != null)
-            {
-                return group.remarks;
-            }
-            return groupId.Substring(0, 4);
+            return group != null ? group.remarks : groupId.Substring(0, 4);
         }
 
         public List<string> GetAlpn()
         {
-            if (alpn != null && alpn.Count > 0)
-            {
-                return alpn;
-            }
-            else
-            {
-                return null;
-            }
+            return alpn is { Count: > 0 } ? alpn : null;
         }
         public string GetNetwork()
         {
diff --git a/v2rayN/v2rayN/Mode/RoutingItem.cs b/v2rayN/v2rayN/Mode/RoutingItem.cs
index 02a93edf..aa141255 100644
--- a/v2rayN/v2rayN/Mode/RoutingItem.cs
+++ b/v2rayN/v2rayN/Mode/RoutingItem.cs
@@ -1,8 +1,5 @@
 using System;
 using System.Collections.Generic;
-using System.Linq;
-using System.Text;
-using System.Threading.Tasks;
 
 namespace v2rayN.Mode
 {
diff --git a/v2rayN/v2rayN/Tool/FileManager.cs b/v2rayN/v2rayN/Tool/FileManager.cs
index 42dffbd6..2c9f12d4 100644
--- a/v2rayN/v2rayN/Tool/FileManager.cs
+++ b/v2rayN/v2rayN/Tool/FileManager.cs
@@ -11,8 +11,8 @@ namespace v2rayN.Tool
         {
             try
             {
-                using (FileStream fs = new FileStream(fileName, FileMode.Create, FileAccess.Write))
-                    fs.Write(content, 0, content.Length);
+                using FileStream fs = new FileStream(fileName, FileMode.Create, FileAccess.Write);
+                fs.Write(content, 0, content.Length);
                 return true;
             }
             catch (Exception ex)
@@ -31,14 +31,12 @@ namespace v2rayN.Tool
                 byte[] buffer = new byte[4096];
                 int n;
 
-                using (FileStream fs = File.Create(fileName))
-                using (GZipStream input = new GZipStream(new MemoryStream(content),
-                        CompressionMode.Decompress, false))
+                using FileStream fs = File.Create(fileName);
+                using GZipStream input = new GZipStream(new MemoryStream(content),
+                    CompressionMode.Decompress, false);
+                while ((n = input.Read(buffer, 0, buffer.Length)) > 0)
                 {
-                    while ((n = input.Read(buffer, 0, buffer.Length)) > 0)
-                    {
-                        fs.Write(buffer, 0, n);
-                    }
+                    fs.Write(buffer, 0, n);
                 }
             }
             catch (Exception ex)
@@ -56,11 +54,9 @@ namespace v2rayN.Tool
         {
             try
             {
-                using (FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite))
-                using (StreamReader sr = new StreamReader(fs, encoding))
-                {
-                    return sr.ReadToEnd();
-                }
+                using FileStream fs = new FileStream(path, FileMode.Open, FileAccess.Read, FileShare.ReadWrite);
+                using StreamReader sr = new StreamReader(fs, encoding);
+                return sr.ReadToEnd();
             }
             catch (Exception ex)
             {
@@ -111,18 +107,16 @@ namespace v2rayN.Tool
         {
             try
             {
-                using (ZipArchive archive = ZipFile.OpenRead(fileName))
+                using ZipArchive archive = ZipFile.OpenRead(fileName);
+                foreach (ZipArchiveEntry entry in archive.Entries)
                 {
-                    foreach (ZipArchiveEntry entry in archive.Entries)
-                    {
-                        if (entry.Length == 0)
-                            continue;
+                    if (entry.Length == 0)
+                        continue;
 
-                        string entryOuputPath = Utils.GetPath(entry.FullName);
-                        FileInfo fileInfo = new FileInfo(entryOuputPath);
-                        fileInfo.Directory.Create();
-                        entry.ExtractToFile(entryOuputPath, true);
-                    }
+                    string entryOuputPath = Utils.GetPath(entry.FullName);
+                    FileInfo fileInfo = new FileInfo(entryOuputPath);
+                    fileInfo.Directory.Create();
+                    entry.ExtractToFile(entryOuputPath, true);
                 }
             }
             catch (Exception ex)
diff --git a/v2rayN/v2rayN/Tool/Job.cs b/v2rayN/v2rayN/Tool/Job.cs
index e2569b75..64b021f1 100644
--- a/v2rayN/v2rayN/Tool/Job.cs
+++ b/v2rayN/v2rayN/Tool/Job.cs
@@ -35,8 +35,7 @@ namespace v2rayN
 
                 if (!SetInformationJobObject(handle, JobObjectInfoType.ExtendedLimitInformation, extendedInfoPtr,
                         (uint) length))
-                    throw new Exception(string.Format("Unable to set information.  Error: {0}",
-                        Marshal.GetLastWin32Error()));
+                    throw new Exception($"Unable to set information.  Error: {Marshal.GetLastWin32Error()}");
             }
             finally
             {
diff --git a/v2rayN/v2rayN/Tool/QueryableExtension.cs b/v2rayN/v2rayN/Tool/QueryableExtension.cs
index eefb04d2..ef264b16 100644
--- a/v2rayN/v2rayN/Tool/QueryableExtension.cs
+++ b/v2rayN/v2rayN/Tool/QueryableExtension.cs
@@ -9,14 +9,14 @@ namespace v2rayN.Tool
     {
         public static IOrderedQueryable<T> OrderBy<T>(this IQueryable<T> query, string propertyName)
         {
-            return _OrderBy<T>(query, propertyName, false);
+            return _OrderBy(query, propertyName, false);
         }
         public static IOrderedQueryable<T> OrderByDescending<T>(this IQueryable<T> query, string propertyName)
         {
-            return _OrderBy<T>(query, propertyName, true);
+            return _OrderBy(query, propertyName, true);
         }
 
-        static IOrderedQueryable<T> _OrderBy<T>(IQueryable<T> query, string propertyName, bool isDesc)
+        private static IOrderedQueryable<T> _OrderBy<T>(IQueryable<T> query, string propertyName, bool isDesc)
         {
             string methodname = (isDesc) ? "OrderByDescendingInternal" : "OrderByInternal";
 
@@ -35,7 +35,8 @@ namespace v2rayN.Tool
         {//public
             return query.OrderByDescending(_GetLamba<T, TProp>(memberProperty));
         }
-        static Expression<Func<T, TProp>> _GetLamba<T, TProp>(PropertyInfo memberProperty)
+
+        private static Expression<Func<T, TProp>> _GetLamba<T, TProp>(PropertyInfo memberProperty)
         {
             if (memberProperty.PropertyType != typeof(TProp)) throw new Exception();
 
diff --git a/v2rayN/v2rayN/Tool/Utils.cs b/v2rayN/v2rayN/Tool/Utils.cs
index 39be59a0..cbd963b0 100644
--- a/v2rayN/v2rayN/Tool/Utils.cs
+++ b/v2rayN/v2rayN/Tool/Utils.cs
@@ -45,11 +45,9 @@ namespace v2rayN
             try
             {
                 Assembly assembly = Assembly.GetExecutingAssembly();
-                using (Stream stream = assembly.GetManifestResourceStream(res))
-                using (StreamReader reader = new StreamReader(stream))
-                {
-                    result = reader.ReadToEnd();
-                }
+                using Stream stream = assembly.GetManifestResourceStream(res);
+                using StreamReader reader = new StreamReader(stream);
+                result = reader.ReadToEnd();
             }
             catch (Exception ex)
             {
@@ -69,10 +67,8 @@ namespace v2rayN
 
             try
             {
-                using (StreamReader reader = new StreamReader(res))
-                {
-                    result = reader.ReadToEnd();
-                }
+                using StreamReader reader = new StreamReader(res);
+                result = reader.ReadToEnd();
             }
             catch (Exception ex)
             {
@@ -385,7 +381,7 @@ namespace v2rayN
         public static string HumanFy(ulong amount)
         {
             ToHumanReadable(amount, out double result, out string unit);
-            return $"{string.Format("{0:f1}", result)} {unit}";
+            return $"{$"{result:f1}"} {unit}";
         }
 
 
@@ -545,29 +541,18 @@ namespace v2rayN
 
         #region 开机自动启动
 
-        private static string autoRunName
-        {
-            get
-            {
-                return $"v2rayNAutoRun_{GetMD5(StartupPath())}";
-            }
-        }
-        private static string autoRunRegPath
-        {
-            get
-            {
-                return @"Software\Microsoft\Windows\CurrentVersion\Run";
-                //if (Environment.Is64BitProcess)
-                //{
-                //    return @"Software\Microsoft\Windows\CurrentVersion\Run";
-                //}
-                //else
-                //{
-                //    return @"SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Run";
-                //}
-            }
-        }
+        private static string autoRunName => $"v2rayNAutoRun_{GetMD5(StartupPath())}";
 
+        private static string autoRunRegPath => @"Software\Microsoft\Windows\CurrentVersion\Run";
+
+        //if (Environment.Is64BitProcess)
+        //{
+        //    return @"Software\Microsoft\Windows\CurrentVersion\Run";
+        //}
+        //else
+        //{
+        //    return @"SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\Run";
+        //}
         /// <summary>
         /// 开机自动启动
         /// </summary>
@@ -703,23 +688,16 @@ namespace v2rayN
         public static bool CheckForDotNetVersion(int release = 528040)
         {
             const string subkey = @"SOFTWARE\Microsoft\NET Framework Setup\NDP\v4\Full\";
-            using (RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey(subkey))
+            using RegistryKey ndpKey = RegistryKey.OpenBaseKey(RegistryHive.LocalMachine, RegistryView.Registry32).OpenSubKey(subkey);
+            if (ndpKey != null && ndpKey.GetValue("Release") != null)
             {
-                if (ndpKey != null && ndpKey.GetValue("Release") != null)
-                {
-                    return (int)ndpKey.GetValue("Release") >= release ? true : false;
-                }
-                return false;
+                return (int)ndpKey.GetValue("Release") >= release ? true : false;
             }
+            return false;
         }
 
-        public static string MainMsgFilterKey
-        {
-            get
-            {
-                return $"MainMsgFilter_{GetMD5(StartupPath())}";
-            }
-        }
+        public static string MainMsgFilterKey => $"MainMsgFilter_{GetMD5(StartupPath())}";
+
         #endregion
 
         #region 测速
@@ -837,14 +815,12 @@ namespace v2rayN
                 string location = GetExePath();
                 if (blFull)
                 {
-                    return string.Format("v2rayN - V{0} - {1}",
-                            FileVersionInfo.GetVersionInfo(location).FileVersion.ToString(),
-                            File.GetLastWriteTime(location).ToString("yyyy/MM/dd"));
+                    return
+                        $"v2rayN - V{FileVersionInfo.GetVersionInfo(location).FileVersion.ToString()} - {File.GetLastWriteTime(location).ToString("yyyy/MM/dd")}";
                 }
                 else
                 {
-                    return string.Format("v2rayN/{0}",
-                        FileVersionInfo.GetVersionInfo(location).FileVersion.ToString());
+                    return $"v2rayN/{FileVersionInfo.GetVersionInfo(location).FileVersion.ToString()}";
                 }
             }
             catch (Exception ex)
@@ -1076,42 +1052,40 @@ namespace v2rayN
             {
                 foreach (Screen screen in Screen.AllScreens)
                 {
-                    using (Bitmap fullImage = new Bitmap(screen.Bounds.Width,
-                                                    screen.Bounds.Height))
+                    using Bitmap fullImage = new Bitmap(screen.Bounds.Width,
+                        screen.Bounds.Height);
+                    using (Graphics g = Graphics.FromImage(fullImage))
                     {
-                        using (Graphics g = Graphics.FromImage(fullImage))
+                        g.CopyFromScreen(screen.Bounds.X,
+                            screen.Bounds.Y,
+                            0, 0,
+                            fullImage.Size,
+                            CopyPixelOperation.SourceCopy);
+                    }
+                    int maxTry = 10;
+                    for (int i = 0; i < maxTry; i++)
+                    {
+                        int marginLeft = (int)((double)fullImage.Width * i / 2.5 / maxTry);
+                        int marginTop = (int)((double)fullImage.Height * i / 2.5 / maxTry);
+                        Rectangle cropRect = new Rectangle(marginLeft, marginTop, fullImage.Width - marginLeft * 2, fullImage.Height - marginTop * 2);
+                        Bitmap target = new Bitmap(screen.Bounds.Width, screen.Bounds.Height);
+
+                        double imageScale = (double)screen.Bounds.Width / (double)cropRect.Width;
+                        using (Graphics g = Graphics.FromImage(target))
                         {
-                            g.CopyFromScreen(screen.Bounds.X,
-                                             screen.Bounds.Y,
-                                             0, 0,
-                                             fullImage.Size,
-                                             CopyPixelOperation.SourceCopy);
+                            g.DrawImage(fullImage, new Rectangle(0, 0, target.Width, target.Height),
+                                cropRect,
+                                GraphicsUnit.Pixel);
                         }
-                        int maxTry = 10;
-                        for (int i = 0; i < maxTry; i++)
+
+                        BitmapLuminanceSource source = new BitmapLuminanceSource(target);
+                        BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
+                        QRCodeReader reader = new QRCodeReader();
+                        Result result = reader.decode(bitmap);
+                        if (result != null)
                         {
-                            int marginLeft = (int)((double)fullImage.Width * i / 2.5 / maxTry);
-                            int marginTop = (int)((double)fullImage.Height * i / 2.5 / maxTry);
-                            Rectangle cropRect = new Rectangle(marginLeft, marginTop, fullImage.Width - marginLeft * 2, fullImage.Height - marginTop * 2);
-                            Bitmap target = new Bitmap(screen.Bounds.Width, screen.Bounds.Height);
-
-                            double imageScale = (double)screen.Bounds.Width / (double)cropRect.Width;
-                            using (Graphics g = Graphics.FromImage(target))
-                            {
-                                g.DrawImage(fullImage, new Rectangle(0, 0, target.Width, target.Height),
-                                                cropRect,
-                                                GraphicsUnit.Pixel);
-                            }
-
-                            BitmapLuminanceSource source = new BitmapLuminanceSource(target);
-                            BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
-                            QRCodeReader reader = new QRCodeReader();
-                            Result result = reader.decode(bitmap);
-                            if (result != null)
-                            {
-                                string ret = result.Text;
-                                return ret;
-                            }
+                            string ret = result.Text;
+                            return ret;
                         }
                     }
                 }
@@ -1128,13 +1102,7 @@ namespace v2rayN
 
         #region Windows API
 
-        public static string WindowHwndKey
-        {
-            get
-            {
-                return $"WindowHwnd_{GetMD5(StartupPath())}";
-            }
-        }
+        public static string WindowHwndKey => $"WindowHwnd_{GetMD5(StartupPath())}";
 
         [DllImport("user32.dll")]
         public static extern bool SetProcessDPIAware();