void StartDrag(MouseEventArgs args)
{
IDataObject data = null;
UIElement dragelement = null;
// ADD THE DATA
if (_callback != null)
{
DragDataWrapper dw = new DragDataWrapper();
data = new DataObject(typeof(DragDataWrapper).ToString(), dw);
if ((_callback.SupportedActions & DragDropProviderActions.MultiFormatData) != 0)
_callback.AppendData(ref data, args);
if ((_callback.SupportedActions & DragDropProviderActions.Data) != 0)
dw.Data = _callback.GetData();
if ((_callback.SupportedActions & DragDropProviderActions.Visual) != 0)
dragelement = _callback.GetVisual(args);
else
dragelement = args.OriginalSource as UIElement;
dw.Source = _dragSource;
dw.Shim = _callback;
System.Diagnostics.Debug.Assert(DragScope == null, "The DragDataWrapper is meant for in-proc... Sorry for asserting, just wanted to confirm.. comment out assertion if needed");
}
else
{
dragelement = args.OriginalSource as UIElement;
data = new DataObject(typeof(UIElement).ToString(), dragelement);
}
if (dragelement == null || data == null || dragelement == this._dragSource)
return;
#if DEBUG
// Add it as Text ... good for testing purposes
if ( !data.GetDataPresent(DataFormats.Text))
data.SetData(DataFormats.Text, "abcd" );
#endif
DragEventHandler dragOver = null;
DragEventHandler dragLeave = null;
QueryContinueDragEventHandler queryContinue = null;
GiveFeedbackEventHandler giveFeedback = null;
DragDropEffects effects = GetDragDropEffects();
DragDropEffects resultEffects;
// Inprocess Drag ...
if (DragScope != null)
{
bool previousAllowDrop = DragScope.AllowDrop;
_adorner = new DragAdorner(DragScope, (UIElement)dragelement, true, Opacity);
_layer = AdornerLayer.GetAdornerLayer(DragScope as Visual);
_layer.Add(_adorner);
if (DragScope != _dragSource)
{
DragScope.AllowDrop = true;
DragDrop.AddPreviewDragOverHandler((DependencyObject)DragScope, dragOver = new DragEventHandler(DragScope_DragOver));
DragDrop.AddPreviewDragLeaveHandler(DragScope, dragLeave = new DragEventHandler(DragScope_DragLeave));
DragDrop.AddPreviewQueryContinueDragHandler(_dragSource, queryContinue = new QueryContinueDragEventHandler(onQueryContinueDrag));
}
try
{
IsDragging = true;
this._mouseLeftScope = false;
resultEffects = DragDrop.DoDragDrop(_dragSource, data, effects);
DragFinished(resultEffects);
}
catch
{
System.Diagnostics.Debug.Assert(false);
}
if (DragScope != _dragSource)
{
DragScope.AllowDrop = previousAllowDrop;
DragDrop.RemovePreviewDragOverHandler(DragScope, dragOver);
DragDrop.RemovePreviewDragLeaveHandler(DragScope, dragLeave);
DragDrop.RemovePreviewQueryContinueDragHandler(_dragSource, queryContinue );
}
}
else
{
DragDrop.AddPreviewQueryContinueDragHandler(_dragSource, queryContinue = new QueryContinueDragEventHandler(onQueryContinueDrag));
DragDrop.AddGiveFeedbackHandler(_dragSource, giveFeedback = new GiveFeedbackEventHandler( onGiveFeedback));
IsDragging = true;
CreateDragDropWindow(dragelement);
this._dragdropWindow.Show();
try
{
resultEffects = DragDrop.DoDragDrop(_dragSource, data, effects);
}
finally { }
DestroyDragDropWindow();
DragDrop.RemovePreviewQueryContinueDragHandler(_dragSource, onQueryContinueDrag);
DragDrop.AddGiveFeedbackHandler(_dragSource, onGiveFeedback);
IsDragging = false;
DragFinished(resultEffects);
}
}
protected void DragFinished(DragDropEffects ret)
{
System.Windows.Input.Mouse.Capture(null);
if (IsDragging)
{
if (DragScope != null)
{
AdornerLayer.GetAdornerLayer(DragScope).Remove(_adorner);
_adorner = null;
}
else
{
DestroyDragDropWindow();
}
}
IsDragging = false;
}