feat(Windows): Address rule CA1822

src/Windows/Avalonia.Win32.Interop/Wpf/Direct2DImageSurface.cs

@@ -113,7 +113,8 @@ namespace Avalonia.Win32.Interop.Wpf
 
         [DllImport("user32.dll", SetLastError = false)]
         private static extern IntPtr GetDesktopWindow();
-        void EnsureDirectX()
+
+        static void EnsureDirectX()
         {
             if(s_d3DDevice != null)
                 return;
@@ -153,7 +154,7 @@ namespace Avalonia.Win32.Interop.Wpf
                 _oldDpi = dpi;
             }
             _impl.ImageSource = _image;
-            
+
             RemoveAndDispose(ref _backBuffer);
             if (size == default(IntSize))
             {
@@ -167,7 +168,7 @@ namespace Avalonia.Win32.Interop.Wpf
             return _backBuffer.Target;
         }
 
-        void RemoveAndDispose<T>(ref T d) where T : IDisposable
+        static void RemoveAndDispose<T>(ref T d) where T : IDisposable
         {
             d?.Dispose();
             d = default(T);

src/Windows/Avalonia.Win32.Interop/Wpf/WpfTopLevelImpl.cs

@@ -142,8 +142,7 @@ namespace Avalonia.Win32.Interop.Wpf
 
         protected override void OnLostFocus(RoutedEventArgs e) => LostFocus?.Invoke();
 
-
-        RawInputModifiers GetModifiers(MouseEventArgs e)
+        static RawInputModifiers GetModifiers(MouseEventArgs e)
         {
             var state = Keyboard.Modifiers;
             var rv = default(RawInputModifiers);

src/Windows/Avalonia.Win32/ClipboardImpl.cs

@@ -15,7 +15,7 @@ namespace Avalonia.Win32
         private const int OleRetryCount = 10;
         private const int OleRetryDelay = 100;
 
-        private async Task<IDisposable> OpenClipboard()
+        private static async Task<IDisposable> OpenClipboard()
         {
             var i = OleRetryCount;
 
@@ -31,7 +31,7 @@ namespace Avalonia.Win32
 
         public async Task<string> GetTextAsync()
         {
-            using(await OpenClipboard())
+            using(await ClipboardImpl.OpenClipboard())
             {
                 IntPtr hText = UnmanagedMethods.GetClipboardData(UnmanagedMethods.ClipboardFormat.CF_UNICODETEXT);
                 if (hText == IntPtr.Zero)
@@ -58,7 +58,7 @@ namespace Avalonia.Win32
                 throw new ArgumentNullException(nameof(text));
             }
 
-            using(await OpenClipboard())
+            using(await ClipboardImpl.OpenClipboard())
             {
                 UnmanagedMethods.EmptyClipboard();
 
@@ -69,7 +69,7 @@ namespace Avalonia.Win32
 
         public async Task ClearAsync()
         {
-            using(await OpenClipboard())
+            using(await ClipboardImpl.OpenClipboard())
             {
                 UnmanagedMethods.EmptyClipboard();
             }

src/Windows/Avalonia.Win32/CursorFactory.cs

@@ -92,7 +92,7 @@ namespace Avalonia.Win32
 
         public ICursorImpl CreateCursor(IBitmapImpl cursor, PixelPoint hotSpot)
         {
-            using var source = LoadSystemDrawingBitmap(cursor);
+            using var source = CursorFactory.LoadSystemDrawingBitmap(cursor);
             using var mask = AlphaToMask(source);
 
             var info = new UnmanagedMethods.ICONINFO
@@ -107,7 +107,7 @@ namespace Avalonia.Win32
             return new CursorImpl(UnmanagedMethods.CreateIconIndirect(ref info), true);
         }
 
-        private SdBitmap LoadSystemDrawingBitmap(IBitmapImpl bitmap)
+        private static SdBitmap LoadSystemDrawingBitmap(IBitmapImpl bitmap)
         {
             using var memoryStream = new MemoryStream();
             bitmap.Save(memoryStream);

src/Windows/Avalonia.Win32/DataObject.cs

@@ -288,10 +288,10 @@ namespace Avalonia.Win32
                 var byteArr = bytes is byte[] ? (byte[])bytes : bytes.ToArray();
                 return WriteBytesToHGlobal(ref hGlobal, byteArr);
             }
-            return WriteBytesToHGlobal(ref hGlobal, SerializeObject(data));
+            return WriteBytesToHGlobal(ref hGlobal, DataObject.SerializeObject(data));
         }
 
-        private byte[] SerializeObject(object data)
+        private static byte[] SerializeObject(object data)
         {
             using (var ms = new MemoryStream())
             {

src/Windows/Avalonia.Win32/PopupImpl.cs

@@ -92,7 +92,7 @@ namespace Avalonia.Win32
                 IntPtr.Zero);
             s_parentHandle = IntPtr.Zero;
 
-            EnableBoxShadow(result, _dropShadowHint);
+            PopupImpl.EnableBoxShadow(result, _dropShadowHint);
 
             return result;
         }
@@ -139,7 +139,7 @@ namespace Avalonia.Win32
             //TODO: We ignore the scaling override for now
         }
 
-        private void EnableBoxShadow (IntPtr hwnd, bool enabled)
+        private static void EnableBoxShadow (IntPtr hwnd, bool enabled)
         {
             var classes = (int)UnmanagedMethods.GetClassLongPtr(hwnd, (int)UnmanagedMethods.ClassLongIndex.GCL_STYLE);
 
@@ -161,7 +161,7 @@ namespace Avalonia.Win32
 
             if (Handle != null)
             {
-                EnableBoxShadow(Handle.Handle, enabled);
+                PopupImpl.EnableBoxShadow(Handle.Handle, enabled);
             }
         }