Added INotifyOnDispose interface

Source/INotifyOnDispose.cs

@@ -0,0 +1,48 @@
+#region Apache License 2.0
+/*
+Nuclex .NET Framework
+Copyright (C) 2002-2024 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;
+using System.Diagnostics;
+
+namespace Nuclex.Support {
+
+  /// <summary>
+  ///   Can be implemented by objects that wish to notify others when they
+  ///   are being disposed, allowing for further cleanup work to be attached
+  /// </summary>
+  /// <remarks>
+  ///   This can be useful if an instance has implicit ownership of certain
+  ///   resources. For example, a view model may have been provided with
+  ///   scoped services via constructor injection. If the view model implements
+  ///   this interface, the scope disposal can be attached to the view model
+  ///   without requiring intrusive boilerplate code inside the view model.
+  /// </remarks>
+  public interface INotifyOnDispose {
+
+    /// <summary>Signals that the object is about to be disposed</summary>
+    /// <remarks>
+    ///   This should be called as the last thing in a Dispose() method and when
+    ///   all objects of which the instance has explicit ownership are already
+    ///   disposed and gone.
+    /// </remarks>
+    event EventHandler Disposing;
+
+  }
+
+} // namespace Nuclex.Support