diff --git a/v2rayN/ServiceLib/Common/Utils.cs b/v2rayN/ServiceLib/Common/Utils.cs
index 1712b40c..fe2b1549 100644
--- a/v2rayN/ServiceLib/Common/Utils.cs
+++ b/v2rayN/ServiceLib/Common/Utils.cs
@@ -425,7 +425,7 @@ public class Utils
         var domain = authority;
 
         // Handle IPv6 addresses, e.g., "[2001:db8::1]:443"
-        if (authority.StartsWith("[") && authority.Contains("]"))
+        if (authority.StartsWith('[') && authority.Contains(']'))
         {
             var closingBracketIndex = authority.LastIndexOf(']');
             if (closingBracketIndex < authority.Length - 1 && authority[closingBracketIndex + 1] == ':')
diff --git a/v2rayN/ServiceLib/Handler/Fmt/SocksFmt.cs b/v2rayN/ServiceLib/Handler/Fmt/SocksFmt.cs
index dbecdade..ae837793 100644
--- a/v2rayN/ServiceLib/Handler/Fmt/SocksFmt.cs
+++ b/v2rayN/ServiceLib/Handler/Fmt/SocksFmt.cs
@@ -45,18 +45,18 @@ public class SocksFmt : BaseFmt
         };
         result = result[Global.ProtocolShares[EConfigType.SOCKS].Length..];
         //remark
-        var indexRemark = result.IndexOf("#");
+        var indexRemark = result.IndexOf('#');
         if (indexRemark > 0)
         {
             try
             {
-                item.Remarks = Utils.UrlDecode(result.Substring(indexRemark + 1, result.Length - indexRemark - 1));
+                item.Remarks = Utils.UrlDecode(result.Substring(indexRemark + 1));
             }
             catch { }
             result = result[..indexRemark];
         }
         //part decode
-        var indexS = result.IndexOf("@");
+        var indexS = result.IndexOf('@');
         if (indexS > 0)
         {
         }
diff --git a/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxRoutingService.cs b/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxRoutingService.cs
index 87cb7c33..b77a227b 100644
--- a/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxRoutingService.cs
+++ b/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxRoutingService.cs
@@ -300,7 +300,7 @@ public partial class CoreConfigSingboxService
 
     private bool ParseV2Domain(string domain, Rule4Sbox rule)
     {
-        if (domain.StartsWith("#") || domain.StartsWith("ext:") || domain.StartsWith("ext-domain:"))
+        if (domain.StartsWith('#') || domain.StartsWith("ext:") || domain.StartsWith("ext-domain:"))
         {
             return false;
         }