Changeset 1105

Timestamp:

6/3/2009 5:57:55 AM (4 years ago)

Author:

lowjoel

Message:

Handle theme changes so when Comctl32.dll v6 is unloaded we revert to .NET rendering (and through the DWM APIs we restore UxTheme? rendering when UxTheme? is reloaded - may not always work but this should suffice)

File:

• trunk/eraser6/Eraser.Util/UxThemeApi.cs (modified) (4 diffs)

trunk/eraser6/Eraser.Util/UxThemeApi.cs

@@ -26 +26 @@
 using System.Windows.Forms;
 using System.Drawing;
+using System.IO;
 
 namespace Eraser.Util
@@ -76 +77 @@
         public static void UpdateControlTheme(ToolStrip menu)
         {
+            //Register for Theme changed messages
+            if (ThemeMessageFilter.Instance == null)
+            {
+                ThemeMessageFilter filter = new ThemeMessageFilter();
+                ThemeMessageFilter.Instance.ThemeChanged += OnThemeChanged;
+            }
+
             if (Environment.OSVersion.Version.Major >= 6)
+            {
+                //Assign our themed renderer for non-custom renderers
+                UXThemeMenuRenderer renderer = new UXThemeMenuRenderer();
                 if (menu.Renderer is ToolStripProfessionalRenderer)
-                    menu.Renderer = new UXThemeMenuRenderer();
+                {
+                    menu.Disposed += OnThemedMenuDisposed;
+                    ThemedMenus.Add(menu, renderer);
+                    if (NativeMethods.ThemesActive)
+                        menu.Renderer = renderer;
+                }
+            }
 
             foreach (ToolStripItem item in menu.Items)
@@ -98 +115 @@
 
         /// <summary>
+        /// Handles the theme changed event - reassigning the renderers to managed
+        /// context menus.
+        /// </summary>
+        private static void OnThemeChanged(object sender, EventArgs e)
+        {
+            bool themesActive = NativeMethods.ThemesActive;
+            foreach (KeyValuePair<ToolStrip, UXThemeMenuRenderer> value in ThemedMenus)
+            {
+                if (themesActive)
+                    value.Key.Renderer = value.Value;
+                else
+                    value.Key.RenderMode = ToolStripRenderMode.ManagerRenderMode;
+            }
+        }
+
+        /// <summary>
+        /// Clean up the reference to the menu when the menu is disposed so we no
+        /// longer track the menu for theme changes.
+        /// </summary>
+        private static void OnThemedMenuDisposed(object sender, EventArgs e)
+        {
+            ThemedMenus.Remove(sender as ToolStrip);
+        }
+
+        /// <summary>
+        /// The private list of menus which has their render changed to the UxTheme renderer.
+        /// This allows us to revert the renderer back to the default Professional
+        /// renderer when we get a theme changed message.
+        /// </summary>
+        private static Dictionary<ToolStrip, UXThemeMenuRenderer> ThemedMenus =
+            new Dictionary<ToolStrip,UXThemeMenuRenderer>();
+
+        /// <summary>
+        /// Filters the Application message loop for WM_THEMECHANGED messages
+        /// and broadcasts them to the event handlers.
+        /// </summary>
+        private class ThemeMessageFilter : IMessageFilter
+        {
+            public ThemeMessageFilter()
+            {
+                if (Instance != null)
+                    throw new InvalidOperationException("Only one instance of the " +
+                        "ThemeMessageFilter can exist at any one time,");
+                Instance = this;
+                ThemesActive = NativeMethods.ThemesActive;
+                Application.AddMessageFilter(this);
+            }
+
+            #region IMessageFilter Members
+            public bool PreFilterMessage(ref Message m)
+            {
+                if (m.Msg == WM_THEMECHANGED)
+                {
+                    ThemesActive = NativeMethods.ThemesActive;
+                    ThemeChanged(null, EventArgs.Empty);
+                }
+                else if (m.Msg == WM_DWMCOMPOSITIONCHANGED)
+                {
+                    if (ThemesActive != NativeMethods.ThemesActive)
+                    {
+                        ThemesActive = NativeMethods.ThemesActive;
+                        ThemeChanged(null, EventArgs.Empty);
+                    }
+                }
+
+                return false;           
+            }
+            #endregion
+
+            /// <summary>
+            /// The global ThemeMessageFilter instance.
+            /// </summary>
+            public static ThemeMessageFilter Instance
+            {
+                get;
+                private set;
+            }
+
+            /// <summary>
+            /// Called when a WM_THEMECHANGED message is sent.
+            /// </summary>
+            public EventHandler<EventArgs> ThemeChanged
+            {
+                get;
+                set;
+            }
+
+            private const int WM_THEMECHANGED = 0x031A;
+            private const int WM_DWMCOMPOSITIONCHANGED = 0x031E;
+            private bool ThemesActive;
+        }
+
+        /// <summary>
         /// Stores functions, structs and constants from UxTheme.dll and User32.dll
         /// </summary>
         internal static class NativeMethods
         {
+            [DllImport("UxTheme.dll", CharSet = CharSet.Unicode)]
+            [return: MarshalAs(UnmanagedType.Bool)]
+            private static extern bool IsThemeActive();
+
+            public static bool ThemesActive
+            {
+                get
+                {
+                    try
+                    {
+                        return IsThemeActive();
+                    }
+                    catch (FileLoadException)
+                    {
+                        return false;
+                    }
+                }
+            }
+
             /// <summary>
             /// Causes a window to use a different set of visual style information
@@ -125 +254 @@
         ~UXThemeMenuRenderer()
         {
-            hTheme.Close();
+            if (hTheme != null)
+                hTheme.Close();
         }