Rest of the platforms

native/Avalonia.Native/src/OSX/clipboard.mm

@@ -148,17 +148,20 @@ public:
     }
 
 
-    virtual HRESULT Clear() override
+    virtual HRESULT Clear(int64_t* rv) override
     {
         START_COM_CALL;
         
         @autoreleasepool
         {
             if(_item != nil)
+            {
                 _item = [NSPasteboardItem new];
+                return 0;
+            }
             else
             {
-                [_pb clearContents];
+                *rv = [_pb clearContents];
                 [_pb setString:@"" forType:NSPasteboardTypeString];
             }
         
@@ -166,6 +169,17 @@ public:
         }
     }
     
+    virtual HRESULT GetChangeCount(int64_t* rv) override
+    {
+        START_COM_CALL;
+        if(_item == nil)
+        {
+            *rv = [_pb changeCount];
+            return S_OK;
+        }
+        return E_NOTIMPL;
+    }
+    
     virtual HRESULT ObtainFormats(IAvnStringArray** ppv) override
     {
         START_COM_CALL;

samples/ControlCatalog/Pages/ClipboardPage.xaml.cs

@@ -167,7 +167,7 @@ namespace ControlCatalog.Pages
             try
             {
                 _checkingClipboardDataObject = true;
-                var task = (TopLevel.GetTopLevel(this)?.Clipboard as IClipboard2)?.TryGetInProcessDataObjectAsync();
+                var task = TopLevel.GetTopLevel(this)?.Clipboard?.TryGetInProcessDataObjectAsync();
                 var owns = task != null && (await task) == _storedDataObject && _storedDataObject != null;
                 OwnsClipboardDataObject.Text = owns ? "Yes" : "No";
                 OwnsClipboardDataObject.Foreground = owns ? Brushes.Green : Brushes.Red;

src/Android/Avalonia.Android/Platform/ClipboardImpl.cs

@@ -55,5 +55,7 @@ namespace Avalonia.Android.Platform
         public Task<string[]> GetFormatsAsync() => throw new PlatformNotSupportedException();
 
         public Task<object?> GetDataAsync(string format) => throw new PlatformNotSupportedException();
+        
+        public Task<IDataObject?> TryGetInProcessDataObjectAsync() => Task.FromResult<IDataObject?>(null);
     }
 }

src/Avalonia.Base/Input/Platform/IClipboard.cs

@@ -17,10 +17,14 @@ namespace Avalonia.Input.Platform
         Task<string[]> GetFormatsAsync();
         
         Task<object?> GetDataAsync(string format);
-    }
-    
-    public interface IClipboard2 : IClipboard
-    {
+        
+        /// <summary>
+        /// If clipboard contains the IDataObject that was set by a previous call to <see cref="SetDataObjectAsync"/>,
+        /// return said IDataObject instance. Otherwise, return null.
+        /// Note that not every platform supports that method, on unsupported platforms this method will always return
+        /// null
+        /// </summary>
+        /// <returns></returns>
         Task<IDataObject?> TryGetInProcessDataObjectAsync();
     }
 }

src/Avalonia.DesignerSupport/Remote/Stubs.cs

@@ -225,6 +225,7 @@ namespace Avalonia.DesignerSupport.Remote
         public Task<string[]> GetFormatsAsync() => Task.FromResult(Array.Empty<string>());
 
         public Task<object> GetDataAsync(string format) => Task.FromResult((object)null);
+        public Task<IDataObject> TryGetInProcessDataObjectAsync() => Task.FromResult<IDataObject>(null);
     }
 
     class CursorFactoryStub : ICursorFactory

src/Avalonia.Native/ClipboardImpl.cs

@@ -17,6 +17,8 @@ namespace Avalonia.Native
     class ClipboardImpl : IClipboard, IDisposable
     {
         private IAvnClipboard? _native;
+        private IDataObject? _savedDataObject;
+        private long _lastClearChangeCount;
 
         // TODO hide native types behind IAvnClipboard abstraction, so managed side won't depend on macOS.
         private const string NSPasteboardTypeString = "public.utf8-plain-text";
@@ -30,10 +32,15 @@ namespace Avalonia.Native
         private IAvnClipboard Native
             => _native ?? throw new ObjectDisposedException(nameof(ClipboardImpl));
 
+        private void ClearCore()
+        {
+            _savedDataObject = null;
+            _lastClearChangeCount = Native.Clear();
+        }
+        
         public Task ClearAsync()
         {
-            Native.Clear();
-
+            ClearCore();
             return Task.CompletedTask;
         }
 
@@ -47,7 +54,7 @@ namespace Avalonia.Native
         {
             var native = Native;
 
-            native.Clear();
+            ClearCore();
 
             if (text != null) 
                 native.SetText(NSPasteboardTypeString, text);
@@ -83,6 +90,7 @@ namespace Avalonia.Native
         
         public void Dispose()
         {
+            _savedDataObject = null;
             _native?.Dispose();
             _native = null;
         }
@@ -111,7 +119,7 @@ namespace Avalonia.Native
 
         public unsafe Task SetDataObjectAsync(IDataObject data)
         {
-            Native.Clear();
+            ClearCore();
 
             // If there is multiple values with the same "to" format, prefer these that were not mapped.
             var formats = data.GetDataFormats().Select(f =>
@@ -163,6 +171,8 @@ namespace Avalonia.Native
                         break;
                 }
             }
+
+            _savedDataObject = data;
             return Task.CompletedTask;
         }
 
@@ -182,6 +192,13 @@ namespace Avalonia.Native
             using (var n = Native.GetBytes(format))
                 return n.Bytes;
         }
+
+        public Task<IDataObject?> TryGetInProcessDataObjectAsync()
+        {
+            if (Native.ChangeCount != _lastClearChangeCount)
+                _savedDataObject = null;
+            return Task.FromResult(_savedDataObject);
+        }
     }
     
     class ClipboardDataObject : IDataObject, IDisposable

src/Avalonia.Native/avn.idl

@@ -2,6 +2,7 @@
 @clr-access internal
 @clr-map bool int
 @clr-map u_int64_t ulong
+@clr-map int64_t long
 @clr-map long IntPtr
 @cpp-preamble @@
 #pragma once
@@ -972,7 +973,8 @@ interface IAvnClipboard : IUnknown
      HRESULT SetBytes(char* type, void* utf8Text, int len);
      HRESULT GetBytes(char* type, IAvnString**ppv);
     
-     HRESULT Clear();
+     HRESULT Clear(int64_t* ret);
+     HRESULT GetChangeCount(int64_t* ret);
 }
 
 [uuid(3f998545-f027-4d4d-bd2a-1a80926d984e)]

src/Avalonia.X11/X11Clipboard.cs

@@ -9,7 +9,7 @@ using Avalonia.Input.Platform;
 using static Avalonia.X11.XLib;
 namespace Avalonia.X11
 {
-    internal class X11Clipboard : IClipboard, IClipboard2
+    internal class X11Clipboard : IClipboard
     {
         private readonly X11Info _x11;
         private IDataObject? _storedDataObject;

src/Browser/Avalonia.Browser/ClipboardImpl.cs

@@ -25,5 +25,7 @@ namespace Avalonia.Browser
         public Task<string[]> GetFormatsAsync() => Task.FromResult(Array.Empty<string>());
 
         public Task<object?> GetDataAsync(string format) => Task.FromResult<object?>(null);
+        
+        public Task<IDataObject?> TryGetInProcessDataObjectAsync() => Task.FromResult<IDataObject?>(null);
     }
 }

src/Headless/Avalonia.Headless/HeadlessPlatformStubs.cs

@@ -23,65 +23,45 @@ namespace Avalonia.Headless
 {
     internal class HeadlessClipboardStub : IClipboard
     {
-        private string? _text;
         private IDataObject? _data;
 
         public Task<string?> GetTextAsync()
         {
-            return Task.Run(() => _text);
+            return Task.FromResult(_data?.GetText());
         }
 
         public Task SetTextAsync(string? text)
         {
-            return Task.Run(() => _text = text);
+            var data = new DataObject();
+            if (text != null)
+                data.Set(DataFormats.Text, text);
+            _data = data;
+            return Task.CompletedTask;
         }
 
         public Task ClearAsync()
         {
-            return Task.Run(() => _text = null);
+            _data = null;
+            return Task.CompletedTask;
         }
 
         public Task SetDataObjectAsync(IDataObject data)
         {
-            return Task.Run(() => _data = data);
+            _data = data;
+            return Task.CompletedTask;
         }
 
         public Task<string[]> GetFormatsAsync()
         {
-            return Task.Run(() =>
-            {
-                if (_data is not null)
-                {
-                    return _data.GetDataFormats().ToArray();
-                }
-
-                if (_text is not null)
-                {
-                    return new[] { DataFormats.Text };
-                }
-
-                return Array.Empty<string>();
-            });
+            return Task.FromResult<string[]>(_data?.GetDataFormats().ToArray() ?? []);
         }
 
-        public async Task<object?> GetDataAsync(string format)
+        public Task<object?> GetDataAsync(string format)
         {
-            return await Task.Run(() =>
-            {
-                if (format == DataFormats.Text)
-                    return _text;
-                if (format == DataFormats.Files && _data is not null)
-                    return _data.GetFiles();
-                if (format == DataFormats.FileNames && _data is not null)
-                {
-#pragma warning disable CS0618 // Type or member is obsolete
-                    return _data.GetFileNames();
-#pragma warning restore CS0618 // Type or member is obsolete
-                }
-                else
-                    return (object?)_data;
-            });
+            return Task.FromResult(_data?.Get(format));
         }
+
+        public Task<IDataObject?> TryGetInProcessDataObjectAsync() => Task.FromResult(_data);
     }
 
     internal class HeadlessCursorFactoryStub : ICursorFactory

src/Tizen/Avalonia.Tizen/NuiClipboardImpl.cs

@@ -73,4 +73,6 @@ internal class NuiClipboardImpl : IClipboard
 
     public Task<string[]> GetFormatsAsync() =>
         throw new PlatformNotSupportedException();
+    
+    public Task<IDataObject?> TryGetInProcessDataObjectAsync() => Task.FromResult<IDataObject?>(null);
 }

src/Windows/Avalonia.Win32/ClipboardImpl.cs

@@ -11,7 +11,7 @@ using MicroCom.Runtime;
 
 namespace Avalonia.Win32
 {
-    internal class ClipboardImpl : IClipboard2
+    internal class ClipboardImpl : IClipboard
     {
         private const int OleRetryCount = 10;
         private const int OleRetryDelay = 100;

src/iOS/Avalonia.iOS/ClipboardImpl.cs

@@ -57,5 +57,7 @@ namespace Avalonia.iOS
 
             return Task.FromResult<object?>(null);
         }
+        
+        public Task<IDataObject?> TryGetInProcessDataObjectAsync() => Task.FromResult<IDataObject?>(null);
     }
 }

tests/Avalonia.Controls.UnitTests/MaskedTextBoxTests.cs

@@ -1005,31 +1005,6 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
-        internal class ClipboardStub : IClipboard // in order to get tests working that use the clipboard
-        {
-            private string _text;
-
-            public Task<string> GetTextAsync() => Task.FromResult(_text);
-
-            public Task SetTextAsync(string text)
-            {
-                _text = text;
-                return Task.CompletedTask;
-            }
-
-            public Task ClearAsync()
-            {
-                _text = null;
-                return Task.CompletedTask;
-            }
-
-            public Task SetDataObjectAsync(IDataObject data) => Task.CompletedTask;
-
-            public Task<string[]> GetFormatsAsync() => Task.FromResult(Array.Empty<string>());
-
-            public Task<object> GetDataAsync(string format) => Task.FromResult((object)null);
-        }
-
         private class TestTopLevel : TopLevel
         {
             private readonly ILayoutManager _layoutManager;
@@ -1048,7 +1023,7 @@ namespace Avalonia.Controls.UnitTests
             var clipboard = new Mock<ITopLevelImpl>();
             clipboard.Setup(x => x.Compositor).Returns(RendererMocks.CreateDummyCompositor());
             clipboard.Setup(r => r.TryGetFeature(typeof(IClipboard)))
-                .Returns(new ClipboardStub());
+                .Returns(new HeadlessClipboardStub());
             clipboard.SetupGet(x => x.RenderScaling).Returns(1);
             return clipboard;
         }

tests/Avalonia.Controls.UnitTests/TextBoxTests.cs

@@ -1973,31 +1973,6 @@ namespace Avalonia.Controls.UnitTests
             }
         }
 
-        private class ClipboardStub : IClipboard // in order to get tests working that use the clipboard
-        {
-            private string? _text;
-
-            public Task<string?> GetTextAsync() => Task.FromResult(_text);
-
-            public Task SetTextAsync(string? text)
-            {
-                _text = text;
-                return Task.CompletedTask;
-            }
-
-            public Task ClearAsync()
-            {
-                _text = null;
-                return Task.CompletedTask;
-            }
-            
-            public Task SetDataObjectAsync(IDataObject data) => Task.CompletedTask;
-
-            public Task<string[]> GetFormatsAsync() => Task.FromResult(Array.Empty<string>());
-
-            public Task<object?> GetDataAsync(string format) => Task.FromResult((object?)null);
-        }
-
         private class TestTopLevel : TopLevel
         {
             private readonly ILayoutManager _layoutManager;
@@ -2016,7 +1991,7 @@ namespace Avalonia.Controls.UnitTests
             var clipboard = new Mock<ITopLevelImpl>();
             clipboard.Setup(x => x.Compositor).Returns(RendererMocks.CreateDummyCompositor());
             clipboard.Setup(r => r.TryGetFeature(typeof(IClipboard)))
-                .Returns(new ClipboardStub());
+                .Returns(new HeadlessClipboardStub());
             clipboard.SetupGet(x => x.RenderScaling).Returns(1);
             return clipboard;
         }