From 1f7609cc2219bf44d76dec1315a3b962bbba418c Mon Sep 17 00:00:00 2001
From: DHR60 <dehongren60@gmail.com>
Date: Sat, 31 Jan 2026 11:44:11 +0800
Subject: [PATCH] Fix

---
 v2rayN/ServiceLib/Common/Utils.cs                    | 12 ++++++++++++
 v2rayN/ServiceLib/Global.cs                          |  7 -------
 .../Services/CoreConfig/Singbox/SingboxDnsService.cs |  8 ++++----
 .../CoreConfig/Singbox/SingboxRoutingService.cs      |  2 +-
 4 files changed, 17 insertions(+), 12 deletions(-)

diff --git a/v2rayN/ServiceLib/Common/Utils.cs b/v2rayN/ServiceLib/Common/Utils.cs
index 0f4feda5..22d10304 100644
--- a/v2rayN/ServiceLib/Common/Utils.cs
+++ b/v2rayN/ServiceLib/Common/Utils.cs
@@ -462,6 +462,18 @@ public class Utils
         return (domain, port);
     }
 
+    public static string? DomainStrategy4Sbox(string? strategy)
+    {
+        return strategy switch
+        {
+            not null when strategy.StartsWith("UseIPv4") => "prefer_ipv4",
+            not null when strategy.StartsWith("UseIPv6") => "prefer_ipv6",
+            not null when strategy.StartsWith("ForceIPv4") => "ipv4_only",
+            not null when strategy.StartsWith("ForceIPv6") => "ipv6_only",
+            _ => null
+        };
+    }
+
     #endregion Conversion Functions
 
     #region Data Checks
diff --git a/v2rayN/ServiceLib/Global.cs b/v2rayN/ServiceLib/Global.cs
index 96fa0a9e..a902bbdd 100644
--- a/v2rayN/ServiceLib/Global.cs
+++ b/v2rayN/ServiceLib/Global.cs
@@ -388,13 +388,6 @@ public class Global
         ""
     ];
 
-    public static readonly Dictionary<string, string> DomainStrategy4SboxMap =
-        DomainStrategy
-            .Where(s => s.StartsWith("UseIPv4", StringComparison.Ordinal) || s.StartsWith("UseIPv6", StringComparison.Ordinal))
-            .ToDictionary(
-                key => key,
-                key => key.StartsWith("UseIPv4", StringComparison.Ordinal) ? "prefer_ipv4" : "prefer_ipv6");
-
     public static readonly List<string> DomainDirectDNSAddress =
     [
         "https://dns.alidns.com/dns-query",
diff --git a/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxDnsService.cs b/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxDnsService.cs
index f9c00caa..6079b2fb 100644
--- a/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxDnsService.cs
+++ b/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxDnsService.cs
@@ -180,13 +180,13 @@ public partial class CoreConfigSingboxService
             new Rule4Sbox
             {
                 server = Global.SingboxRemoteDNSTag,
-                strategy = Global.DomainStrategy4SboxMap.GetValueOrDefault(simpleDNSItem.Strategy4Proxy),
+                strategy = Utils.DomainStrategy4Sbox(simpleDNSItem.Strategy4Proxy),
                 clash_mode = ERuleMode.Global.ToString()
             },
             new Rule4Sbox
             {
                 server = Global.SingboxDirectDNSTag,
-                strategy = Global.DomainStrategy4SboxMap.GetValueOrDefault(simpleDNSItem.Strategy4Freedom),
+                strategy = Utils.DomainStrategy4Sbox(simpleDNSItem.Strategy4Freedom),
                 clash_mode = ERuleMode.Direct.ToString()
             }
         });
@@ -309,7 +309,7 @@ public partial class CoreConfigSingboxService
             if (item.OutboundTag == Global.DirectTag)
             {
                 rule.server = Global.SingboxDirectDNSTag;
-                rule.strategy = Global.DomainStrategy4SboxMap.GetValueOrDefault(simpleDNSItem.Strategy4Freedom);
+                rule.strategy = Utils.DomainStrategy4Sbox(simpleDNSItem.Strategy4Freedom);
 
                 if (expectedIPsRegions.Count > 0 && rule.geosite?.Count > 0)
                 {
@@ -343,7 +343,7 @@ public partial class CoreConfigSingboxService
                     singboxConfig.dns.rules.Add(rule4Fake);
                 }
                 rule.server = Global.SingboxRemoteDNSTag;
-                rule.strategy = Global.DomainStrategy4SboxMap.GetValueOrDefault(simpleDNSItem.Strategy4Proxy);
+                rule.strategy = Utils.DomainStrategy4Sbox(simpleDNSItem.Strategy4Proxy);
             }
 
             singboxConfig.dns.rules.Add(rule);
diff --git a/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxRoutingService.cs b/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxRoutingService.cs
index 68d04a7e..9424df78 100644
--- a/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxRoutingService.cs
+++ b/v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxRoutingService.cs
@@ -10,7 +10,7 @@ public partial class CoreConfigSingboxService
             var simpleDnsItem = _config.SimpleDNSItem;
 
             var defaultDomainResolverTag = Global.SingboxDirectDNSTag;
-            var directDnsStrategy = Global.DomainStrategy4SboxMap.GetValueOrDefault(simpleDnsItem.Strategy4Freedom);
+            var directDnsStrategy = Utils.DomainStrategy4Sbox(simpleDnsItem.Strategy4Freedom);
 
             var rawDNSItem = await AppManager.Instance.GetDNSItem(ECoreType.sing_box);
             if (rawDNSItem is { Enabled: true })