ConventionBinder now binds IDialogViewModel.Submit to close the associated view

Source/AutoBinding/ConventionBinder.cs

@@ -21,6 +21,9 @@ using System;
 
 using Avalonia.Controls;
 
+using Nuclex.Avalonia.ViewModels;
+using Nuclex.Avalonie.ViewModels;
+
 namespace Nuclex.Avalonia.AutoBinding {
 
   /// <summary>
@@ -55,6 +58,27 @@ namespace Nuclex.Avalonia.AutoBinding {
     /// <param name="view">View that will be bound</param>
     /// <param name="viewModel">View model the view will be bound to</param>
     private void bind(Control view, object viewModel) {
+      IDialogViewModel? dialogViewModel = viewModel as IDialogViewModel;
+      if(dialogViewModel != null) {
+        Window? viewAsWindow = view as Window;
+        if(viewAsWindow != null) {
+          EventHandler<DialogResultEventArgs> handler = (
+            delegate(object sender, DialogResultEventArgs arguments) {
+              viewAsWindow.Close(arguments.Result);
+            }
+          );
+
+          dialogViewModel.Submitted += handler;
+
+          // Does this help anything?
+          // Without it, the view has a reference to the view model (via DataContext),
+          // and the view model references the view (via event subscription), but this
+          // shouldn't bother the .NET garbage collector at all.
+          viewAsWindow.Closed += delegate(object sender, EventArgs arguments) {
+            dialogViewModel.Submitted -= handler;
+          };
+        }
+      }
     }
 
   }

Source/ViewModels/DialogResultEventArgs.cs

@@ -0,0 +1,43 @@
+#region Apache License 2.0
+/*
+Nuclex Foundation libraries for .NET
+Copyright (C) 2002-2025 Markus Ewald / Nuclex Development Labs
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+#endregion // Apache License 2.0
+
+using System;
+
+namespace Nuclex.Avalonia.ViewModels {
+
+  /// <summary>Carries the desired dialog result from a view model</summary>
+  public class DialogResultEventArgs : EventArgs {
+
+    /// <summary>Initializes a new dialog result event argument container</summary>
+    /// <param name="result">Result the dialog should exit with</param>
+    public DialogResultEventArgs(object result) {
+      this.result = result;
+    }
+
+    /// <summary>Result that should be returned from the dialog</summary>
+    public object Result {
+      get { return this.result; }
+    }
+
+    /// <summary>Result that should be returned from the dialog</summary>
+    private readonly object result;
+
+  }
+
+} // namespace Nuclex.Avalonia.ViewModels

Source/ViewModels/IDialogViewModel.cs

@@ -20,20 +20,21 @@ limitations under the License.
 using System;
 using System.Threading.Tasks;
 
-using Nuclex.Support;
+using Nuclex.Avalonia.ViewModels;
 
-namespace Nuclex.Windows.Forms.ViewModels {
+namespace Nuclex.Avalonie.ViewModels {
 
   /// <summary>Interface for dialog view models (typically modal ones)</summary>
   public interface IDialogViewModel {
 
     /// <summary>Indicates that the view should close</summary>
-    event EventHandler Submitted;
+    event EventHandler<DialogResultEventArgs> Submitted;
 
     /// <summary>Indicates that the dialog should be closed</summary>
+    /// <param name="dialogResult">Result the dialog should return</param>
     /// <returns>A task that finishes when the submit notification has been sent</returns>
-    Task SubmitAsync();
+    Task SubmitAsync(object? dialogResult = null);
 
   }
 
-} // namespace Nuclex.Windows.Forms.ViewModels
+} // namespace Nuclex.Avalonie.ViewModels