Dark Mode issues Fixes

src/System.Private.Windows.Core/src/Windows/Win32/PInvokeCore.GetSysColorBrush.cs

@@ -7,7 +7,15 @@ namespace Windows.Win32;
 
 internal static partial class PInvokeCore
 {
-    /// <inheritdoc cref="GetSysColorBrush(SYS_COLOR_INDEX)"/>
+    private static HBRUSH s_solidBrush;
+    private static HBRUSH s_lastSolidBruch;
+
+    /// <summary>
+    /// Returns a system color brush for the given color.
+    /// If using an alternative color set, manages solid brush creation and cleanup to prevent GDI leaks.
+    /// </summary>
+    /// <param name="systemColor">The system color.</param>
+    /// <returns>An HBRUSH for the color.</returns>
     public static HBRUSH GetSysColorBrush(Color systemColor)
     {
 #if NET9_0_OR_GREATER
@@ -20,13 +28,35 @@ public static HBRUSH GetSysColorBrush(Color systemColor)
 
         if (useSolidBrush)
         {
-            // We don't have a real system color, so we'll just create a solid brush.
-            return CreateSolidBrush(systemColor);
+            // Create a new solid brush for the alternative color set.
+            s_solidBrush = CreateSolidBrush(systemColor);
+
+            // Delete the previous solid brush to avoid GDI leaks.
+            if (s_lastSolidBruch != s_solidBrush)
+            {
+                if (s_lastSolidBruch != default)
+                {
+                    DeleteObject(s_lastSolidBruch);
+                }
+
+                s_lastSolidBruch = s_solidBrush;
+            }
+
+            return s_solidBrush;
         }
 
         Debug.Assert(systemColor.IsSystemColor);
 
-        // Extract the COLOR value
+        // Clean up any previously created solid brushes to prevent GDI leaks.
+        if (s_solidBrush != default || s_lastSolidBruch != default)
+        {
+            DeleteObject(s_solidBrush);
+            DeleteObject(s_lastSolidBruch);
+            s_solidBrush = default;
+            s_lastSolidBruch = default;
+        }
+
+        // Return the system color brush for the specified system color.
         return GetSysColorBrush((SYS_COLOR_INDEX)(ColorTranslator.ToOle(systemColor) & 0xFF));
     }
 }

src/System.Windows.Forms.Primitives/src/NativeMethods.txt

@@ -165,7 +165,9 @@ GetKeyState
 GetLocaleInfoEx
 GetMapMode
 GetMenu
+GetMenuBarInfo
 GetMenuItemCount
+GetMenuItemRect
 GetMenuItemInfo
 GetMessage
 GetMessagePos
@@ -224,6 +226,7 @@ GetWindow
 GetWindowDisplayAffinity
 GetWindowDpiAwarenessContext
 GetWindowPlacement
+GetWindowTheme
 GetWorldTransform
 GMR_*
 HC_*
@@ -454,6 +457,7 @@ MONTHCAL_CLASS
 MOUSEHOOKSTRUCT
 MoveToEx
 MSFTEDIT_CLASS
+MSGF_*
 MsgWaitForMultipleObjectsEx
 NavigateDirection
 NFR_*
@@ -488,6 +492,7 @@ NOTIFY_ICON_INFOTIP_FLAGS
 NOTIFY_ICON_MESSAGE
 NotifyWinEvent
 OemKeyScan
+OffsetRect
 OLECLOSE
 OLECMDEXECOPT
 OLECMDF

src/System.Windows.Forms/System/Windows/Forms/Application.cs

@@ -313,6 +313,7 @@ public static void SetColorMode(SystemColorMode systemColorMode)
             {
                 SystemColors.UseAlternativeColorSet = darkModeEnabled;
                 NotifySystemEventsOfColorChange();
+                PInvokeCore.EnumWindows(SendThemeChanged);
             }
         }
 
@@ -723,8 +724,8 @@ private static BOOL SendThemeChangedRecursive(HWND handle)
     {
         // First send to all children.
         PInvokeCore.EnumChildWindows(handle, SendThemeChangedRecursive);
-
-        // Then send to ourself.
+        // Send the theme changed message to this window.
+        PInvokeCore.SendMessage(handle, PInvokeCore.WM_SYSCOLORCHANGE);
         PInvokeCore.SendMessage(handle, PInvokeCore.WM_THEMECHANGED);
 
         return true;

src/System.Windows.Forms/System/Windows/Forms/Control.cs

@@ -5851,7 +5851,8 @@ internal virtual HBRUSH InitializeDCForWmCtlColor(HDC dc, MessageId msg)
         {
             PInvokeCore.SetTextColor(dc, (COLORREF)(uint)ColorTranslator.ToWin32(ForeColor));
             PInvokeCore.SetBkColor(dc, (COLORREF)(uint)ColorTranslator.ToWin32(BackColor));
-            return BackColorBrush;
+            // Avoid redundant caching; use the existing brush if already owned
+            return GetState(States.OwnCtlBrush) ? BackColorBrush : PInvokeCore.GetSysColorBrush(BackColor);
         }
 
         return (HBRUSH)PInvokeCore.GetStockObject(GET_STOCK_OBJECT_FLAGS.NULL_BRUSH);
@@ -8082,9 +8083,11 @@ protected virtual void OnSystemColorsChanged(EventArgs e)
             for (int i = 0; i < children.Count; i++)
             {
                 children[i].OnSystemColorsChanged(EventArgs.Empty);
+                OnThemChanged(children[i]);
             }
         }
 
+        OnThemChanged(this);
         Invalidate();
 
         ((EventHandler?)Events[s_systemColorsChangedEvent])?.Invoke(this, e);
@@ -10391,15 +10394,11 @@ protected virtual void SetVisibleCore(bool value)
                 {
                     // We shouldn't mess with the color mode if users haven't specifically set it.
                     // https://github.com/dotnet/winforms/issues/12014
-                    if (value && Application.ColorModeSet)
-                    {
-                        PrepareDarkMode(HWND, Application.IsDarkModeEnabled);
-                    }
-
+                    // I Don't think we should be doing this for Forms here , but it is the same as the old code but execute Form Control.
                     PInvoke.ShowWindow(HWND, value ? ShowParams : SHOW_WINDOW_CMD.SW_HIDE);
                 }
             }
-#pragma warning restore WFO5001
+#pragma warning restore WFO5001w
             else if (IsHandleCreated || (value && _parent?.Created == true))
             {
                 // We want to mark the control as visible so that CreateControl
@@ -10487,17 +10486,6 @@ protected virtual void SetVisibleCore(bool value)
                         | (value ? SET_WINDOW_POS_FLAGS.SWP_SHOWWINDOW : SET_WINDOW_POS_FLAGS.SWP_HIDEWINDOW));
             }
         }
-
-        static unsafe void PrepareDarkMode(HWND hwnd, bool darkModeEnabled)
-        {
-            BOOL value = darkModeEnabled;
-
-            PInvoke.DwmSetWindowAttribute(
-                hwnd,
-                DWMWINDOWATTRIBUTE.DWMWA_USE_IMMERSIVE_DARK_MODE,
-                &value,
-                (uint)sizeof(BOOL)).AssertSuccess();
-        }
     }
 
     /// <summary>
@@ -11098,6 +11086,67 @@ internal void WindowReleaseHandle()
         _window.ReleaseHandle();
     }
 
+    /// <summary>
+    /// Updates the visual theme of the specified control based on the application's current theme settings.
+    /// This method applies the appropriate theme to the specified control depending on whether the application is in dark mode or light mode.
+    /// </summary>
+    /// <param name="control">The control whose theme is to be updated. Supported controls include <see cref="ProgressBar"/>, <see
+    /// cref="ComboBox"/>, <see cref="ListView"/>, and others.</param>
+    private void OnThemChanged(Control control)
+    {
+#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+        if (control.GetStyle(ControlStyles.ApplyThemingImplicitly))
+        {
+            switch (control)
+            {
+            case ProgressBar:
+                string? isDarkTheme = Application.IsDarkModeEnabled ? "" : null;
+                PInvoke.SetWindowTheme(HWND, isDarkTheme, isDarkTheme);
+                break;
+            case ComboBox:
+                {
+                    PInvoke.SetWindowTheme(HWND,
+                        Application.IsDarkModeEnabled
+                        ? $"{DarkModeIdentifier}_{ComboBoxButtonThemeIdentifier}"
+                        : null, null);
+                    COMBOBOXINFO cInfo = default;
+                    cInfo.cbSize = (uint)sizeof(COMBOBOXINFO);
+                    _ = PInvoke.GetComboBoxInfo(HWND, ref cInfo);
+                    PInvoke.SetWindowTheme(cInfo.hwndList,
+                        Application.IsDarkModeEnabled
+                        ? $"{DarkModeIdentifier}_{ExplorerThemeIdentifier}"
+                        : null, null);
+                    PInvokeCore.SendMessage(cInfo.hwndList, PInvokeCore.WM_THEMECHANGED);
+                    PInvokeCore.SendMessage(HWND, PInvokeCore.WM_THEMECHANGED);
+                }
+
+                break;
+            case ListView:
+                PInvoke.SetWindowTheme(HWND,
+                     Application.IsDarkModeEnabled
+                     ? $"{DarkModeIdentifier}_{ExplorerThemeIdentifier}"
+                     : null, null);
+
+                // Get the ListView's ColumnHeader handle:
+                HWND columnHeaderHandle = (HWND)PInvokeCore.SendMessage(this, PInvoke.LVM_GETHEADER, (WPARAM)0, (LPARAM)0);
+                PInvoke.SetWindowTheme(columnHeaderHandle, Application.IsDarkModeEnabled
+                    ? $"{DarkModeIdentifier}_{ItemsViewThemeIdentifier}"
+                    : null,
+                    null);
+                break;
+            default:
+                // For all other controls, we set the theme to the Explorer theme.
+                PInvoke.SetWindowTheme(HWNDInternal,
+                    Application.IsDarkModeEnabled
+                        ? $"{DarkModeIdentifier}_{ExplorerThemeIdentifier}"
+                        : null, null);
+                break;
+        }
+        }
+#pragma warning restore WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+
+    }
+
     private void WmClose(ref Message m)
     {
         if (ParentInternal is not null)
@@ -11786,6 +11835,39 @@ private void WmOwnerDraw(ref Message m)
         DefWndProc(ref m);
     }
 
+    /// <summary>
+    ///  Handles the WM_DWMNCRENDERINGCHANGED message, which is sent when the Desktop Window Manager (DWM) non-client area rendering policy changes.
+    ///  This message allows the control to update its appearance or behavior in response to changes in DWM rendering, such as enabling or disabling
+    ///  dark mode for window, borders and title bar Colors.
+    /// </summary>
+    private unsafe void WmDwmNcRenderingChanged(ref Message m)
+    {
+        DefWndProc(ref m);
+
+        // 1. Check if the control's handle is created and  Desktop Window Manager (DWM) non-client area rendering policy is enabled.
+        // 2. If so, update the non-client rendering (e.g., update window frame, invalidate non-client area).
+
+        // Specifies whether DWM rendering is enabled for the non-client area of the window. WPARAM is TRUE if enabled; otherwise, FALSE.
+        if (m.WParamInternal != 0)
+        {
+            bool hasDarkNcArea;
+            if (PInvoke.DwmGetWindowAttribute(m.HWND, DWMWINDOWATTRIBUTE.DWMWA_USE_IMMERSIVE_DARK_MODE, &hasDarkNcArea, sizeof(int)).Succeeded)
+            {
+#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+                if (Application.IsDarkModeEnabled == hasDarkNcArea)
+                {
+                    // No change in dark mode state, no need to update.
+                    return;
+                }
+
+                hasDarkNcArea = Application.IsDarkModeEnabled;
+                PInvoke.DwmSetWindowAttribute(m.HWND, DWMWINDOWATTRIBUTE.DWMWA_USE_IMMERSIVE_DARK_MODE, &hasDarkNcArea, sizeof(int));
+#pragma warning restore WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+
+            }
+        }
+    }
+
     /// <summary>
     ///  Handles the WM_PAINT messages. This should only be called for userpaint controls.
     /// </summary>
@@ -12517,7 +12599,9 @@ protected virtual void WndProc(ref Message m)
             case MessageId.WM_REFLECT_NOTIFYFORMAT:
                 m.ResultInternal = (LRESULT)(nint)PInvoke.NFR_UNICODE;
                 break;
-
+            case PInvokeCore.WM_DWMNCRENDERINGCHANGED:
+                WmDwmNcRenderingChanged(ref m);
+                break;
             case PInvokeCore.WM_SHOWWINDOW:
                 WmShowWindow(ref m);
                 break;
@@ -12564,8 +12648,28 @@ protected virtual void WndProc(ref Message m)
                 break;
 
             case PInvokeCore.WM_SETTINGCHANGE:
-                if (GetExtendedState(ExtendedStates.InterestedInUserPreferenceChanged) && GetTopLevel())
-                {
+                if (GetExtendedState(ExtendedStates.InterestedInUserPreferenceChanged))
+                {
+#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+                    Application.SetColorMode(Application.ColorMode);
+
+                    const string DarkModeThemeIdentifier = $"{DarkModeIdentifier}_{ExplorerThemeIdentifier}";
+                    PInvoke.SetWindowTheme(m.HWND,
+                        Application.IsDarkModeEnabled
+                        ? DarkModeThemeIdentifier
+                        : default,
+                        null);
+                    PInvoke.RedrawWindow(
+                        m.HWND,
+                        lprcUpdate: (RECT*)null,
+                        HRGN.Null,
+                        REDRAW_WINDOW_FLAGS.RDW_INVALIDATE
+                        | REDRAW_WINDOW_FLAGS.RDW_FRAME
+                        | REDRAW_WINDOW_FLAGS.RDW_ERASE
+                        | REDRAW_WINDOW_FLAGS.RDW_ALLCHILDREN);
+                    if (!GetTopLevel())
+                        return;
+#pragma warning restore WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
                     SYSTEM_PARAMETERS_INFO_ACTION action = (SYSTEM_PARAMETERS_INFO_ACTION)(uint)m.WParamInternal;
 
                     // Left here for debugging purposes.
@@ -12612,7 +12716,6 @@ protected virtual void WndProc(ref Message m)
                 }
 
                 break;
-
             case PInvokeCore.WM_SYSCOLORCHANGE:
                 if (GetExtendedState(ExtendedStates.InterestedInUserPreferenceChanged) && GetTopLevel())
                 {

src/System.Windows.Forms/System/Windows/Forms/Controls/Buttons/ButtonBase.cs

@@ -1347,6 +1347,25 @@ private void ResetUseVisualStyleBackColor()
         Invalidate();
     }
 
+    private void WmSysColorChange(ref Message m)
+    {
+        base.WndProc(ref m);
+#pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+
+        // If  disabled DarkMode, we need to update the button's appearance
+        // to reflect the new color scheme.
+        if (FlatStyle == FlatStyle.Standard && !Application.IsDarkModeEnabled)
+        {
+            if (OwnerDraw != GetStyle(ControlStyles.UserPaint))
+            {
+                SetStyle(ControlStyles.UserMouse | ControlStyles.UserPaint, OwnerDraw);
+                _cachedAdapterType = default;
+            }
+        }
+#pragma warning restore WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
+
+    }
+
     private bool ShouldSerializeUseVisualStyleBackColor() => _isEnableVisualStyleBackgroundSet;
 
     protected override void WndProc(ref Message m)
@@ -1366,6 +1385,9 @@ protected override void WndProc(ref Message m)
                 }
 
                 return;
+            case PInvokeCore.WM_SYSCOLORCHANGE:
+                WmSysColorChange(ref m);
+                break;
         }
 
         if (OwnerDraw)

src/System.Windows.Forms/System/Windows/Forms/Controls/ComboBox/ComboBox.cs

@@ -330,6 +330,10 @@ protected override CreateParams CreateParams
     {
         get
         {
+#pragma warning disable WFO5001
+            SetStyle(ControlStyles.ApplyThemingImplicitly, true);
+#pragma warning restore WFO5001
+
             CreateParams cp = base.CreateParams;
             cp.ClassName = PInvoke.WC_COMBOBOX;
             cp.Style |= (int)WINDOW_STYLE.WS_VSCROLL | PInvoke.CBS_HASSTRINGS | PInvoke.CBS_AUTOHSCROLL;
@@ -2335,7 +2339,7 @@ protected override unsafe void OnHandleCreated(EventArgs e)
         }
 
 #pragma warning disable WFO5001 // Type is for evaluation purposes only and is subject to change or removal in future updates. Suppress this diagnostic to proceed.
-        if (Application.IsDarkModeEnabled)
+        if (Application.IsDarkModeEnabled &&GetStyle(ControlStyles.ApplyThemingImplicitly))
         {
             // Style the ComboBox Open-Button:
             PInvoke.SetWindowTheme(HWND, $"{DarkModeIdentifier}_{ComboBoxButtonThemeIdentifier}", null);