private void StartDrag(MouseEventArgs args) { IDataObject data = null; UIElement dragelement = null; // ADD THE DATA if (this.Callback != null) { DragDataWrapper dw = new DragDataWrapper(); data = new DataObject(typeof(DragDataWrapper).ToString(), dw); if ((this.Callback.SupportedActions & DragDropProviderActions.MultiFormatData) != 0) { this.Callback.AppendData(ref data, args); } if ((this.Callback.SupportedActions & DragDropProviderActions.Data) != 0) { dw.Data = this.Callback.GetData(); } if ((this.Callback.SupportedActions & DragDropProviderActions.Visual) != 0) { dragelement = this.Callback.GetVisual(args); } else { dragelement = args.OriginalSource as UIElement; } dw.Source = this.DragSource; dw.Shim = this.Callback; Debug.Assert(this.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; } DragEventHandler dragOver = null; DragEventHandler dragLeave = null; QueryContinueDragEventHandler queryContinue = null; GiveFeedbackEventHandler giveFeedback = null; DragDropEffects effects = this.GetDragDropEffects(); DragDropEffects resultEffects; // Inprocess Drag ... if (this.DragScope != null) { bool previousAllowDrop = this.DragScope.AllowDrop; this.adorner = new DragAdorner(this.DragScope, (UIElement)dragelement, true, this.Opacity); this.layer = AdornerLayer.GetAdornerLayer(this.DragScope as Visual); this.layer.Add(this.adorner); if (this.DragScope != this.DragSource) { this.DragScope.AllowDrop = true; DragDrop.AddPreviewDragOverHandler((DependencyObject)this.DragScope, dragOver = new DragEventHandler(DragScope_DragOver)); DragDrop.AddPreviewDragLeaveHandler(this.DragScope, dragLeave = new DragEventHandler(DragScope_DragLeave)); DragDrop.AddPreviewQueryContinueDragHandler(this.DragSource, queryContinue = new QueryContinueDragEventHandler(OnQueryContinueDrag)); } try { this.IsDragging = true; this.mouseLeftScope = false; resultEffects = DragDrop.DoDragDrop(this.DragSource, data, effects); this.DragFinished(resultEffects); } catch { Debug.Assert(false); } if (this.DragScope != this.DragSource) { this.DragScope.AllowDrop = previousAllowDrop; DragDrop.RemovePreviewDragOverHandler(this.DragScope, dragOver); DragDrop.RemovePreviewDragLeaveHandler(this.DragScope, dragLeave); DragDrop.RemovePreviewQueryContinueDragHandler(this.DragSource, queryContinue); } } else { DragDrop.AddPreviewQueryContinueDragHandler(this.DragSource, queryContinue = new QueryContinueDragEventHandler(OnQueryContinueDrag)); DragDrop.AddGiveFeedbackHandler(this.DragSource, giveFeedback = new GiveFeedbackEventHandler(OnGiveFeedback)); this.IsDragging = true; if ((this.Callback.SupportedActions & DragDropProviderActions.Visual) != 0) { this.CreateDragDropWindow(dragelement); this.dragdropWindow.Show(); } try { resultEffects = DragDrop.DoDragDrop(this.DragSource, data, effects); } finally { } if ((this.Callback.SupportedActions & DragDropProviderActions.Visual) != 0) { this.DestroyDragDropWindow(); } DragDrop.RemovePreviewQueryContinueDragHandler(this.DragSource, OnQueryContinueDrag); DragDrop.AddGiveFeedbackHandler(this.DragSource, OnGiveFeedback); this.IsDragging = false; this.DragFinished(resultEffects); } }