Merge pull request #444 from dmg-hamann/develop

fix touch support 

src/GongSolutions.WPF.DragDrop/DragDrop.Properties.cs

@@ -1660,5 +1660,34 @@ public static void SetDropTargetItemsSorter(DependencyObject element, IDropTarge
         {
             element.SetValue(DropTargetItemsSorterProperty, value);
         }
+        
+        /// <summary>
+        /// Gets or sets the mouse move triggered by a timer.
+        /// </summary>
+        public static readonly DependencyProperty MouseMoveTimerTriggeredProperty
+            = DependencyProperty.RegisterAttached("MouseMoveTimerTriggered",
+                                                  typeof(bool),
+                                                  typeof(DragDrop),
+                                                  new PropertyMetadata(false));
+
+        /// <summary>Helper for getting <see cref="MouseMoveTimerTriggeredProperty"/> from <paramref name="element"/>.</summary>
+        /// <param name="element"><see cref="DependencyObject"/> to read <see cref="MouseMoveTimerTriggeredProperty"/> from.</param>
+        /// <remarks>Gets the mouse move triggered by a timer.</remarks>
+        /// <returns>MouseMoveTimerTriggered property value.</returns>
+        [AttachedPropertyBrowsableForType(typeof(UIElement))]
+        public static bool GetMouseMoveTimerTriggered(DependencyObject element)
+        {
+            return (bool)element.GetValue(MouseMoveTimerTriggeredProperty);
+        }
+
+        /// <summary>Helper for setting <see cref="MouseMoveTimerTriggeredProperty"/> on <paramref name="element"/>.</summary>
+        /// <param name="element"><see cref="DependencyObject"/> to set <see cref="MouseMoveTimerTriggeredProperty"/> on.</param>
+        /// <param name="value">MouseMoveTimerTriggered property value.</param>
+        /// <remarks>Sets the mouse move triggered by a timer.</remarks>
+        [AttachedPropertyBrowsableForType(typeof(UIElement))]
+        public static void SetMouseMoveTimerTriggered(DependencyObject element, bool value)
+        {
+            element.SetValue(MouseMoveTimerTriggeredProperty, value);
+        }
     }
 }
\ No newline at end of file

src/GongSolutions.WPF.DragDrop/DragDrop.cs

@@ -639,11 +639,12 @@ private static void DoDragSourceMove(object sender, Func<IInputElement, Point> g
                                     DragDropPreview?.Move(getPosition(DragDropPreview.PlacementTarget));
                                 }
 
-                                hookId = MouseHelper.HookMouseMove(point =>
-                                    {
-                                        DragDropPreview?.Move(CursorHelper.GetCurrentCursorPosition(DragDropPreview.PlacementTarget, point));
-                                        DragDropEffectPreview?.Move(CursorHelper.GetCurrentCursorPosition(DragDropEffectPreview.PlacementTarget, point));
-                                    });
+                                hookId = MouseHelper.HookMouseMove(DragDrop.GetMouseMoveTimerTriggered(dragInfo.VisualSource),
+                                                                   point =>
+                                                                       {
+                                                                           DragDropPreview?.Move(CursorHelper.GetCurrentCursorPosition(DragDropPreview.PlacementTarget, point));
+                                                                           DragDropEffectPreview?.Move(CursorHelper.GetCurrentCursorPosition(DragDropEffectPreview.PlacementTarget, point));
+                                                                       });
 
                                 var dragDropHandler = dragInfo.DragDropHandler ?? System.Windows.DragDrop.DoDragDrop;
                                 var dragDropEffects = dragDropHandler(dragInfo.VisualSource, dataObject, dragInfo.Effects);

src/GongSolutions.WPF.DragDrop/Utilities/MouseHelper.cs

@@ -11,29 +11,50 @@ internal static class MouseHelper
 
         private const int WH_MOUSE_LL = 14;
 
-        private static IntPtr _hookID = IntPtr.Zero;
+        private static bool _timerTriggered;
         private static Action<System.Windows.Point> _mouseMoveHandler;
 
         // wee need to keep the variable to prevent the GarbageCollector to remove the HookCallback
         // https://social.msdn.microsoft.com/Forums/vstudio/en-US/68fdc3dc-8d77-48c4-875c-5312baa56aee/how-to-fix-callbackoncollecteddelegate-exception?forum=netfxbcl
         private static LowLevelMouseProc _proc = HookCallback;
+        private static System.Windows.Threading.DispatcherTimer _timer;
 
-        internal static IntPtr HookMouseMove(Action<System.Windows.Point> mouseMoveHandler)
+        internal static IntPtr HookMouseMove(bool timerTriggered, Action<System.Windows.Point> mouseMoveHandler)
         {
             _mouseMoveHandler = mouseMoveHandler;
+            _timerTriggered = timerTriggered;
 
-            using (var process = Process.GetCurrentProcess())
+            if (_timerTriggered)
             {
-                using (var module = process.MainModule)
-                {
-                    return SetWindowsHookEx(WH_MOUSE_LL, _proc, GetModuleHandle(module.ModuleName), 0);
-                }
+                _timer = new System.Windows.Threading.DispatcherTimer(System.Windows.Threading.DispatcherPriority.Input);
+                _timer.Tick += (_, _) =>
+                    {
+                        if (TryGetCursorPos(out var lpPoint))
+                        {
+                            _mouseMoveHandler?.Invoke(new System.Windows.Point(lpPoint.x, lpPoint.y));
+                        }
+                    };
+                _timer.Interval = new TimeSpan(1);
+                _timer.Start();
+
+                return IntPtr.Zero;
             }
+
+            using var process = Process.GetCurrentProcess();
+            using var module = process.MainModule;
+            return module != null ? SetWindowsHookEx(WH_MOUSE_LL, _proc, GetModuleHandle(module.ModuleName), 0) : IntPtr.Zero;
         }
 
         internal static void RemoveHook(IntPtr hookId)
         {
-            UnhookWindowsHookEx(hookId);
+            if (_timerTriggered)
+            {
+                _timer.Stop();
+            }
+            else
+            {
+                UnhookWindowsHookEx(hookId);
+            }
         }
 
         private static IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
@@ -41,12 +62,11 @@ private static IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
             if (nCode >= 0 && MouseMessages.WM_MOUSEMOVE == (MouseMessages)wParam)
             {
                 MSLLHOOKSTRUCT hookStruct = (MSLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(MSLLHOOKSTRUCT));
-                //Debug.WriteLine(hookStruct.pt.x + ", " + hookStruct.pt.y);
                 var mousePosScreen = new System.Windows.Point(hookStruct.pt.x, hookStruct.pt.y);
                 _mouseMoveHandler?.Invoke(mousePosScreen);
             }
 
-            return CallNextHookEx(_hookID, nCode, wParam, lParam);
+            return CallNextHookEx(IntPtr.Zero, nCode, wParam, lParam);
         }
 
         private enum MouseMessages
@@ -88,5 +108,25 @@ private struct MSLLHOOKSTRUCT
 
         [DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
         private static extern IntPtr GetModuleHandle(string lpModuleName);
+
+        [DllImport("user32.dll", EntryPoint = "GetCursorPos", ExactSpelling = true, CharSet = CharSet.Auto, SetLastError = true)]
+        [return: MarshalAs(UnmanagedType.Bool)]
+        private static extern bool _GetCursorPos(out POINT lpPoint);
+
+        private static bool TryGetCursorPos(out POINT pt)
+        {
+            var returnValue = _GetCursorPos(out pt);
+            // Sometimes Win32 will fail this call, such as if you are
+            // not running in the interactive desktop. For example,
+            // a secure screen saver may be running.
+            if (!returnValue)
+            {
+                Trace.WriteLine("GetCursorPos failed!");
+                pt.x = 0;
+                pt.y = 0;
+            }
+
+            return returnValue;
+        }
     }
 }
\ No newline at end of file

src/Showcase/Views/ListBoxSamples.xaml

@@ -43,6 +43,7 @@
                                          dd:DragDrop.IsDragSource="True"
                                          dd:DragDrop.IsDropTarget="True"
                                          dd:DragDrop.UseDefaultEffectDataTemplate="True"
+                                         dd:DragDrop.MouseMoveTimerTriggered="True"
                                          ItemsSource="{Binding Data.Collection1}" />
                                 <ListBox x:Name="RightBoundListBox"
                                          Grid.Column="1"

src/Showcase/Views/SettingsView.xaml

@@ -11,32 +11,45 @@
     <StackPanel>
         <TextBlock Style="{StaticResource DefaultTextBlockStyle}"
                    Text="{Binding ElementName=This, Path=Caption, Mode=OneWay}" />
-        <CheckBox Margin="10 5 5 5"
+        <CheckBox Margin="10 2 2 2"
                   Content="IsDragSource"
+                  ToolTip="Sets whether the control can be used as drag source."
                   IsChecked="{Binding Path=(dd:DragDrop.IsDragSource), Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
-        <CheckBox Margin="10 5 5 5"
+        <CheckBox Margin="10 2 2 2"
                   Content="IsDropTarget"
+                  ToolTip="Sets whether the control can be used as drop target."
                   IsChecked="{Binding Path=(dd:DragDrop.IsDropTarget), Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
-        <CheckBox Margin="10 5 5 5"
+        <CheckBox Margin="10 2 2 2"
                   Content="DragDirectlySelectedOnly"
+                  ToolTip="Sets whether the drag action should be started only directly on a selected item or also on the free control space (e.g. in a ListBox)."
                   IsChecked="{Binding Path=(dd:DragDrop.DragDirectlySelectedOnly), Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
-        <CheckBox Margin="10 5 5 5"
+        <CheckBox Margin="10 2 2 2"
                   Content="ShowAlwaysDropTargetAdorner"
+                  ToolTip="Sets whether to show the DropTargetAdorner (DropTargetInsertionAdorner) on an empty target too."
                   IsChecked="{Binding Path=(dd:DragDrop.ShowAlwaysDropTargetAdorner), Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
-        <CheckBox Margin="10 5 5 5"
+        <CheckBox Margin="10 2 2 2"
                   Content="SelectDroppedItems"
+                  ToolTip="Sets whether if the dropped items should be select again (should keep the selection)."
                   IsChecked="{Binding Path=(dd:DragDrop.SelectDroppedItems), Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
-        <CheckBox Margin="10 5 5 5"
+        <CheckBox Margin="10 2 2 2"
                   Content="CanDragWithMouseRightButton"
+                  ToolTip="Sets whether the control can be used as drag source together with the right mouse."
                   IsChecked="{Binding Path=(dd:DragDrop.CanDragWithMouseRightButton), Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
-        <CheckBox Margin="10 5 5 5"
+        <CheckBox Margin="10 2 2 2"
                   Content="UseDefaultDragAdorner"
+                  ToolTip="Sets whether if the default DragAdorner should be use."
                   IsChecked="{Binding Path=(dd:DragDrop.UseDefaultDragAdorner), Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
-        <CheckBox Margin="10 5 5 5"
+        <CheckBox Margin="10 2 2 2"
                   Content="UseVisualSourceItemSizeForDragAdorner"
+                  ToolTip="Use descendant bounds of the VisualSourceItem as MinWidth for the DragAdorner."
                   IsChecked="{Binding Path=(dd:DragDrop.UseVisualSourceItemSizeForDragAdorner), Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
-        <CheckBox Margin="10 5 5 5"
+        <CheckBox Margin="10 2 2 2"
                   Content="UseDefaultEffectDataTemplate"
+                  ToolTip="Sets whether if the default DataTemplate for the effects should be use."
                   IsChecked="{Binding Path=(dd:DragDrop.UseDefaultEffectDataTemplate), Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
+        <CheckBox Margin="10 2 2 2"
+                  Content="MouseMoveTimerTriggered"
+                  ToolTip="Sets the mouse move triggered by a timer."
+                  IsChecked="{Binding Path=(dd:DragDrop.MouseMoveTimerTriggered), Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" />
     </StackPanel>
 </UserControl>
\ No newline at end of file