Fix bind interface handling in desktop and sing-box (#9258)

* Fix desktop bind interface setting

* Fix sing-box bind interface config

* Update CoreConfigSingboxServiceTests.cs

---------

Co-authored-by: 2dust <31833384+2dust@users.noreply.github.com>

v2rayN/ServiceLib.Tests/CoreConfig/Singbox/CoreConfigSingboxServiceTests.cs

@@ -54,6 +54,29 @@ public class CoreConfigSingboxServiceTests
         cfg.inbounds.Should().Contain(i => i.type == "tun");
     }
 
+    [Fact]
+    public void GenerateClientConfigContent_BindInterface_ShouldUseDialBindInterface()
+    {
+        var config = CoreConfigTestFactory.CreateConfig(ECoreType.sing_box);
+        config.CoreBasicItem.BindInterface = "eth0";
+        CoreConfigTestFactory.BindAppManagerConfig(config);
+
+        var node = CoreConfigTestFactory.CreateVmessNode(ECoreType.sing_box);
+        var context = CoreConfigTestFactory.CreateContext(config, node, ECoreType.sing_box) with
+        {
+            IsTunEnabled = true,
+        };
+
+        var result = new CoreConfigSingboxService(context).GenerateClientConfigContent();
+
+        result.Success.Should().BeTrue($"ret msg: {result.Msg}");
+        var cfg = JsonUtils.Deserialize<SingboxConfig>(result.Data!.ToString())!;
+        var proxy = cfg.outbounds.First(o => o.tag == Global.ProxyTag);
+
+        proxy.bind_interface.Should().Be("eth0");
+        proxy.detour.Should().BeNullOrEmpty();
+    }
+
     [Fact]
     public void GenerateClientConfigContent_PolicyGroup_ShouldExpandChildrenAndBuildSelector()
     {

v2rayN/ServiceLib/Services/CoreConfig/Singbox/SingboxConfigTemplateService.cs

@@ -72,7 +72,7 @@ public partial class CoreConfigSingboxService
         }
         foreach (var outbound in _coreConfig.outbounds ?? [])
         {
-            outbound.detour = ShouldBindNet(outbound) ? bindInterface : null;
+            outbound.bind_interface = ShouldBindNet(outbound) ? bindInterface : null;
         }
     }
 

v2rayN/v2rayN.Desktop/Views/OptionSettingWindow.axaml.cs

@@ -77,6 +77,7 @@ public partial class OptionSettingWindow : WindowBase<OptionSettingViewModel>
             this.Bind(ViewModel, vm => vm.defAllowInsecure, v => v.togdefAllowInsecure.IsChecked).DisposeWith(disposables);
             this.Bind(ViewModel, vm => vm.defFingerprint, v => v.cmbdefFingerprint.SelectedValue).DisposeWith(disposables);
             this.Bind(ViewModel, vm => vm.defUserAgent, v => v.cmbdefUserAgent.SelectedValue).DisposeWith(disposables);
+            this.Bind(ViewModel, vm => vm.bindInterface, v => v.txtbindInterface.Text).DisposeWith(disposables);
             this.Bind(ViewModel, vm => vm.sendThrough, v => v.txtsendThrough.Text).DisposeWith(disposables);
             this.Bind(ViewModel, vm => vm.mux4SboxProtocol, v => v.cmbmux4SboxProtocol.SelectedValue).DisposeWith(disposables);
             this.Bind(ViewModel, vm => vm.enableCacheFile4Sbox, v => v.togenableCacheFile4Sbox.IsChecked).DisposeWith(disposables);