WPF NotifyIcon

--------------
Initial import

git-svn-id: https://svn.evolvesoftware.ch/repos/evolve.net/WPF/NotifyIcon@52 9f600761-6f11-4665-b6dc-0185e9171623

Source/NotifyIconWpf/Interop/WindowMessageSink.Handle.cs

@@ -0,0 +1,102 @@
+using System;
+using System.ComponentModel;
+
+namespace Hardcodet.Wpf.TaskbarNotification.Interop
+{
+  /// <summary>
+  /// Provides low level code that is used to receive
+  /// window messages without having a window that
+  /// prevents a WPF application from shutting down
+  /// properly.
+  /// </summary>
+  public partial class WindowMessageSink
+  {
+    /// <summary>
+    /// Window class ID.
+    /// </summary>
+    private string WindowId;
+    
+    /// <summary>
+    /// Handle for the message window.
+    /// </summary
+    internal IntPtr MessageWindowHandle { get; private set; }
+    
+    /// <summary>
+    /// The ID of the message that is being received if the
+    /// taskbar is (re)started.
+    /// </summary>
+    private uint taskbarRestartMessageId;
+    
+    /// <summary>
+    /// A delegate that processes messages of the hidden
+    /// native window that receives window messages. Storing
+    /// this reference makes sure we don't loose our reference
+    /// to the message window.
+    /// </summary>
+    private WindowProcedureHandler messageHandler;
+
+    /// <summary>
+    /// Creates the helper message window that is used
+    /// to receive messages from the taskbar icon.
+    /// </summary>
+    private void CreateMessageWindow()
+    {
+      WindowId = "WPFTaskbarIcon_" + Guid.NewGuid().ToString();
+
+      //register window message handler
+      messageHandler = OnWindowMessageReceived;
+
+      // Create a simple window class which is reference through
+      //the messageHandler delegate
+      WindowClass wc;
+
+      wc.style = 0;
+      wc.lpfnWndProc = messageHandler;
+      wc.cbClsExtra = 0;
+      wc.cbWndExtra = 0;
+      wc.hInstance = IntPtr.Zero;
+      wc.hIcon = IntPtr.Zero;
+      wc.hCursor = IntPtr.Zero;
+      wc.hbrBackground = IntPtr.Zero;
+      wc.lpszMenuName = "";
+      wc.lpszClassName = WindowId;
+
+      // Register the window class
+      WinApi.RegisterClass(ref wc);
+
+      // Get the message used to indicate the taskbar has been restarted
+      // This is used to re-add icons when the taskbar restarts
+      taskbarRestartMessageId = WinApi.RegisterWindowMessage("TaskbarCreated");
+
+      // Create the message window
+      MessageWindowHandle = WinApi.CreateWindowEx(0, WindowId, "", 0, 0, 0, 1, 1, 0, 0, 0, 0);
+
+      if (MessageWindowHandle == IntPtr.Zero)
+      {
+        throw new Win32Exception();
+      }
+    }
+
+
+
+    /// <summary>
+    /// Callback method that receives messages from the taskbar area.
+    /// </summary>
+    private long OnWindowMessageReceived(IntPtr hwnd, uint messageId, uint wparam, uint lparam)
+    {      
+      if (messageId == taskbarRestartMessageId)
+      {
+        //recreate the icon if the taskbar was restarted
+        //TODO refresh icon
+      }
+
+      ProcessWindowMessage(messageId, wparam, lparam);
+
+      //handle mouse clicks...
+
+      // Pass the message to the default window procedure
+      return WinApi.DefWindowProc(hwnd, messageId, wparam, lparam);
+    }
+
+  }
+}