protected override void OnBeginDrag() { if (this.DraggedElements.Count > MoveStrategy.GetMaxChildrenForElement((SceneElement)this.LayoutContainer, (IProperty)null)) { throw new InvalidOperationException(ExceptionStringTable.BehaviorCannotHandleMultipleElements); } this.PrepareDraggedElementsForDragging(); }
private static MoveStrategy CreateForLayoutMode(MoveStrategyContext context, SceneElement hitElement) { SceneElement sceneElement = hitElement; while (sceneElement != null) { BaseFrameworkElement frameworkElement = sceneElement as BaseFrameworkElement; if (frameworkElement != null && context.RootNode.IsAncestorOf((SceneNode)frameworkElement)) { if (!MoveStrategyFactory.CanMoveInside(context, frameworkElement)) { sceneElement = frameworkElement.ParentElement; continue; } MoveStrategy byParentType = MoveStrategyFactory.CreateByParentType(context, frameworkElement); if (byParentType != null) { bool flag = false; ItemsControlElement itemsControlElement = frameworkElement.ParentElement as ItemsControlElement; ContentControlElement contentControlElement = frameworkElement as ContentControlElement; if (itemsControlElement != null && contentControlElement != null && (ItemsControlElement.ItemsProperty.Equals((object)itemsControlElement.GetPropertyForChild((SceneNode)frameworkElement)) && (itemsControlElement.ViewObject as IViewItemsControl).IsItemItsOwnContainer(contentControlElement.ViewObject))) { flag = true; } if (!flag) { IProperty contentProperty = MoveStrategyFactory.GetContentProperty(context, (SceneNode)frameworkElement); int childrenForElement = MoveStrategy.GetMaxChildrenForElement((SceneElement)frameworkElement, contentProperty); if (context.DraggedElements.Count <= childrenForElement && (childrenForElement != 1 || context.DraggedElements.Count != 1 || (!frameworkElement.IsAncestorOf((SceneNode)context.DraggedElements[0]) || context.DraggedElements[0].Parent == frameworkElement))) { byParentType.LayoutContainer = frameworkElement; return(byParentType); } } } } if (sceneElement != context.RootNode) { sceneElement = sceneElement.ParentElement; } else { break; } } return((MoveStrategy)null); }