Add EnsureHandleSafe extension and use it

QuickLook.Common/ExtensionMethods/WindowInteropHelperExtension.cs

@@ -0,0 +1,40 @@
+// Copyright © 2017-2026 QL-Win Contributors
+//
+// This file is part of QuickLook program.
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+using System;
+using System.Windows.Interop;
+
+namespace QuickLook.Common.ExtensionMethods;
+
+public static class WindowInteropHelperExtension
+{
+    extension(WindowInteropHelper windowInteropHelper)
+    {
+        public nint EnsureHandleSafe()
+        {
+            try
+            {
+                return windowInteropHelper?.EnsureHandle() ?? IntPtr.Zero;
+            }
+            catch
+            {
+                // Returning 0 is fine, since this error usually only occurs when the window is already closed or being disposed.
+                return IntPtr.Zero;
+            }
+        }
+    }
+}