private void AdornerMouseUp(object sender, MouseEventArgs e)
{
switch (adorner.AdornerDropState)
{
case DropState.CanDrop:
DropElement();
break;
case DropState.CannotDrop:
DoNotDropElement();
break;
}
lastDraggedElement = null;
adornerLayer.PreviewMouseMove -= AdornerMouseMove;
adornerLayer.PreviewMouseUp -= AdornerMouseUp;
if (adorner != null)
{
adorner.ReleaseMouseCapture();
}
adorner = null;
mouseCaptured = false;
}
// Drag = mouse down + move by a certain amount
private void OnDragSourcePreviewMouseMove(object sender, MouseEventArgs e)
{
if (!mouseCaptured && lastDraggedElement != null)
{
// Only drag when user moved the mouse by a reasonable amount.
if (IsMovementBigEnough(initialMousePosition, e.GetPosition(topWindow)))
{
adorner = (DragDropAdorner)GetDragDropControl(sender as DependencyObject);
adorner.DataContext = lastDraggedElement.DataContext;
adorner.Opacity = 0.7;
adornerLayer.Visibility = Visibility.Visible;
adornerLayer.Children.Add(adorner);
mouseCaptured = Mouse.Capture(adorner);
Canvas.SetLeft(adorner, initialMousePosition.X - 20);
Canvas.SetTop(adorner, initialMousePosition.Y - 15);
adornerLayer.PreviewMouseMove += AdornerMouseMove;
adornerLayer.PreviewMouseUp += AdornerMouseUp;
}
}
}
/// <summary>
/// Make a <see cref="DependencyObject" /> draggable.
/// </summary>
/// <param name="dependencyObject">The object to make draggable</param>
/// <param name="dropTargets">The drop targets names.</param>
/// <param name="dragDropAdorner">The drag drop adorner implementation to use.</param>
/// <param name="adornerLayerName">The adorner view layer.</param>
public static void MakeObjectDraggable(DependencyObject dependencyObject, IEnumerable <string> dropTargets, DragDropAdorner dragDropAdorner, string adornerLayerName)
{
string targets = string.Join(",", dropTargets);
dependencyObject.SetValue(DragDropHelper.IsDragSourceProperty, true);
dependencyObject.SetValue(DragDropHelper.DropTargetsProperty, targets);
dependencyObject.SetValue(DragDropHelper.AdornerLayerProperty, adornerLayerName);
dependencyObject.SetValue(DragDropHelper.DragDropControlProperty, dragDropAdorner);
}
private static void DropStateChanged(DependencyObject d, DependencyPropertyChangedEventArgs e)
{
DragDropAdorner myclass = (DragDropAdorner)d;
myclass.StateChangedHandler(d, e);
}
