Fixed issue where a blank window appears in Alt+Tab in Windows

DevToys-app · Nov 17, 2024 · 0caee9c · 0caee9c
1 parent 0cb94b7
commit 0caee9c
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Showing 3 changed files with 14 additions and 12 deletions.
diff --git a/src/app/dev/platforms/desktop/DevToys.Windows/Controls/OverlayWindow.xaml.cs b/src/app/dev/platforms/desktop/DevToys.Windows/Controls/OverlayWindow.xaml.cs
@@ -1,5 +1,7 @@
 using System.Windows;
 using System.Windows.Interop;
+using DevToys.Windows.Native;
+using Windows.Win32.Foundation;
 
 namespace DevToys.Windows.Controls;
 
@@ -18,6 +20,9 @@ protected override void OnSourceInitialized(EventArgs e)
         var hwndSource = HwndSource.FromHwnd(windowHandle);
         hwndSource.AddHook(new HwndSourceHook(WndProc));
 
+        // Hide window from Alt+Tab.
+        NativeMethods.HideFromAltTab(new HWND(windowHandle));
+
         base.OnSourceInitialized(e);
     }
 

diff --git a/src/app/dev/platforms/desktop/DevToys.Windows/Native/HwndSourceMessages.cs b/src/app/dev/platforms/desktop/DevToys.Windows/Native/HwndSourceMessages.cs
@@ -3,4 +3,5 @@
 internal static class HwndSourceMessages
 {
     internal const int WS_CHILD = 0x40000000;
+    internal const int WS_EX_TOOLWINDOW = 0x00000080;
 }
diff --git a/src/app/dev/platforms/desktop/DevToys.Windows/Native/NativeMethods.cs b/src/app/dev/platforms/desktop/DevToys.Windows/Native/NativeMethods.cs
@@ -9,56 +9,52 @@ namespace DevToys.Windows.Native;
 
 internal static partial class NativeMethods
 {
+#pragma warning disable CA1416 // Validate platform compatibility
     internal static unsafe HRESULT SetWindowAttribute(HWND windowHandle, DWMWINDOWATTRIBUTE attribute, ref int parameter)
     {
-#pragma warning disable CA1416 // Validate platform compatibility
         fixed (void* value = &parameter)
         {
             return PInvoke.DwmSetWindowAttribute(windowHandle, attribute, value, (uint)Marshal.SizeOf<int>());
         }
-#pragma warning restore CA1416 // Validate platform compatibility
     }
 
     internal static int ExtendFrame(HWND windowHandle, MARGINS margins)
     {
-#pragma warning disable CA1416 // Validate platform compatibility
         return PInvoke.DwmExtendFrameIntoClientArea(windowHandle, in margins);
-#pragma warning restore CA1416 // Validate platform compatibility
     }
 
     internal static void HideAllWindowButton(HWND windowHandle)
     {
-#pragma warning disable CA1416 // Validate platform compatibility
         _ = PInvoke.SetWindowLong(windowHandle, WINDOW_LONG_PTR_INDEX.GWL_STYLE, PInvoke.GetWindowLong(windowHandle, WINDOW_LONG_PTR_INDEX.GWL_STYLE) & ~HwndButtons.WS_SYSMENU);
-#pragma warning restore CA1416 // Validate platform compatibility
     }
 
     internal static void SetWindowAsChildOf(HWND windowHandleChild, HWND windowHandleParent)
     {
-#pragma warning disable CA1416 // Validate platform compatibility
         PInvoke.SetWindowLong(windowHandleChild, WINDOW_LONG_PTR_INDEX.GWL_STYLE, HwndSourceMessages.WS_CHILD);
         PInvoke.SetParent(windowHandleChild, windowHandleParent);
-#pragma warning restore CA1416 // Validate platform compatibility
     }
 
     internal static void DisableMinimizeAndMaximizeCapabilities(HWND windowHandle)
     {
-#pragma warning disable CA1416 // Validate platform compatibility
         HMENU systemMenuHandle = PInvoke.GetSystemMenu(windowHandle, false);
         PInvoke.EnableMenuItem(systemMenuHandle, (uint)PInvoke.SC_MAXIMIZE, MENU_ITEM_FLAGS.MF_BYCOMMAND | MENU_ITEM_FLAGS.MF_GRAYED);
         PInvoke.EnableMenuItem(systemMenuHandle, (uint)PInvoke.SC_MINIMIZE, MENU_ITEM_FLAGS.MF_BYCOMMAND | MENU_ITEM_FLAGS.MF_GRAYED);
-#pragma warning restore CA1416 // Validate platform compatibility
     }
 
     internal static void EnableMinimizeAndMaximizeCapabilities(HWND windowHandle)
     {
-#pragma warning disable CA1416 // Validate platform compatibility
         HMENU systemMenuHandle = PInvoke.GetSystemMenu(windowHandle, false);
         PInvoke.EnableMenuItem(systemMenuHandle, (uint)PInvoke.SC_MAXIMIZE, MENU_ITEM_FLAGS.MF_BYCOMMAND | MENU_ITEM_FLAGS.MF_ENABLED);
         PInvoke.EnableMenuItem(systemMenuHandle, (uint)PInvoke.SC_MINIMIZE, MENU_ITEM_FLAGS.MF_BYCOMMAND | MENU_ITEM_FLAGS.MF_ENABLED);
-#pragma warning restore CA1416 // Validate platform compatibility
     }
 
+    internal static void HideFromAltTab(HWND windowHandle)
+    {
+        int currentStyle = PInvoke.GetWindowLong(windowHandle, WINDOW_LONG_PTR_INDEX.GWL_EXSTYLE);
+        PInvoke.SetWindowLong(windowHandle, WINDOW_LONG_PTR_INDEX.GWL_EXSTYLE, currentStyle | HwndSourceMessages.WS_EX_TOOLWINDOW);
+    }
+
+#pragma warning restore CA1416 // Validate platform compatibility
     /// <summary>
     /// Sets various information regarding DWM window attributes
     /// </summary>