static bool UpdateEffects(object uiObject, DragEventArgs e)
{
try
{
DropTargetBase advisor = GetDropTarget(uiObject as DependencyObject);
if (advisor.IsValidDataObject(e.Data) == false)
{
return(false);
}
if ((e.AllowedEffects & DragDropEffects.Move) == 0 &&
(e.AllowedEffects & DragDropEffects.Copy) == 0)
{
e.Effects = DragDropEffects.None;
return(true);
}
if ((e.AllowedEffects & DragDropEffects.Move) != 0 &&
(e.AllowedEffects & DragDropEffects.Copy) != 0)
{
if ((e.KeyStates & DragDropKeyStates.ControlKey) != 0)
{
}
e.Effects = ((e.KeyStates & DragDropKeyStates.ControlKey) != 0) ?
DragDropEffects.Copy : DragDropEffects.Move;
}
return(true);
}
catch (Exception ex)
{
VMuktiHelper.ExceptionHandler(ex, "UpdateEffects()", "Controls\\VMuktiGrid\\DragDropManager\\DragDropManager.cs");
return(false);
}
}
/* ____________________________________________________________________
* Drop Target events
* ____________________________________________________________________
*/
static void DropTarget_PreviewDrop(object sender, DragEventArgs e)
{
try
{
if (UpdateEffects(sender, e) == false)
{
return;
}
DropTargetBase advisor = GetDropTarget(sender as DependencyObject);
Point dropPoint = e.GetPosition(sender as UIElement);
// Calculate displacement for (Left, Top)
Point offset = e.GetPosition(_overlayElt);
dropPoint.X = dropPoint.X - offset.X;
dropPoint.Y = dropPoint.Y - offset.Y;
advisor.OnDropCompleted(e.Data, dropPoint);
RemovePreviewAdorner();
_offsetPoint = new Point(0, 0);
}
catch (Exception ex)
{
VMuktiHelper.ExceptionHandler(ex, "DropTarget_PreviewDrop()", "Controls\\VMuktiGrid\\DragDropManager\\DragDropManager.cs");
}
}
static void DropTarget_PreviewDragLeave(object sender, DragEventArgs e)
{
try
{
if (UpdateEffects(sender, e) == false)
{
return;
}
DropTargetBase advisor = GetDropTarget(sender as DependencyObject);
Point mousePoint = MouseUtilities.GetMousePosition(advisor.TargetUI);
//Console.WriteLine("Inside DropTarget_PreviewDragLeave1" + mousePoint.X.ToString() + "|" + mousePoint.Y.ToString());
//giving a tolerance of 2 so that the adorner is removed when the mouse is moved fast.
//this might still be small...in that case increase the tolerance
if ((mousePoint.X < 2) || (mousePoint.Y < 2) ||
(mousePoint.X > ((FrameworkElement)(advisor.TargetUI)).ActualWidth - 2) ||
(mousePoint.Y > ((FrameworkElement)(advisor.TargetUI)).ActualHeight - 2))
{
RemovePreviewAdorner();
}
e.Handled = true;
}
catch (Exception ex)
{
VMuktiHelper.ExceptionHandler(ex, "DropTarget_PreviewDragLeave()", "Controls\\VMuktiGrid\\DragDropManager\\DragDropManager.cs");
}
}
private static void OnDropTargetChanged(DependencyObject depObj, DependencyPropertyChangedEventArgs args)
{
try
{
UIElement targetElt = depObj as UIElement;
if (args.NewValue != null && args.OldValue == null)
{
targetElt.PreviewDragEnter += new DragEventHandler(DropTarget_PreviewDragEnter);
targetElt.PreviewDragOver += new DragEventHandler(DropTarget_PreviewDragOver);
targetElt.PreviewDragLeave += new DragEventHandler(DropTarget_PreviewDragLeave);
targetElt.PreviewDrop += new DragEventHandler(DropTarget_PreviewDrop);
targetElt.AllowDrop = true;
// Set the Drag source UI
DropTargetBase advisor = args.NewValue as DropTargetBase;
advisor.TargetUI = targetElt;
}
else if (args.NewValue == null && args.OldValue != null)
{
targetElt.PreviewDragEnter -= DropTarget_PreviewDragEnter;
targetElt.PreviewDragOver -= DropTarget_PreviewDragOver;
targetElt.PreviewDragLeave -= DropTarget_PreviewDragLeave;
targetElt.PreviewDrop -= DropTarget_PreviewDrop;
targetElt.AllowDrop = false;
}
}
catch (Exception ex)
{
VMuktiHelper.ExceptionHandler(ex, "OnDropTargetChanged()", "Controls\\VMuktiGrid\\DragDropManager\\DragDropManager.cs");
}
}
static void DropTarget_PreviewDragEnter(object sender, DragEventArgs e)
{
try
{
if (UpdateEffects(sender, e) == false)
{
return;
}
// Setup the preview Adorner
UIElement feedbackUI = GetDropTarget(sender as DependencyObject).GetVisualFeedback(e.Data);
_offsetPoint = GetOffsetPoint(e.Data);
DropTargetBase advisor = GetDropTarget(sender as DependencyObject);
Point mousePoint = MouseUtilities.GetMousePosition(advisor.TargetUI);
// Console.WriteLine("Inside DropTarget_PreviewDragEnter" + mousePoint.X.ToString() + "|" + mousePoint.Y.ToString());
//giving a tolerance of 2 so that the adorner is created when the mouse is moved fast.
//this might still be small...in that case increase the tolerance
if ((mousePoint.X < 2) || (mousePoint.Y < 2) ||
(mousePoint.X > ((FrameworkElement)(advisor.TargetUI)).ActualWidth - 2) ||
(mousePoint.Y > ((FrameworkElement)(advisor.TargetUI)).ActualHeight - 2) ||
(_overlayElt == null))
{
CreatePreviewAdorner(sender as UIElement, feedbackUI);
}
e.Handled = true;
}
catch (Exception ex)
{
VMuktiHelper.ExceptionHandler(ex, "DropTarget_PreviewDragEnter()", "Controls\\VMuktiGrid\\DragDropManager\\DragDropManager.cs");
}
}
