UIElement.PreviewQueryContinueDrag 事件
定義
拖放操作期間，鍵盤或滑鼠按鈕狀態變更時發生。Occurs when there is a change in the keyboard or mouse button state during a drag-and-drop operation.
public:
event System::Windows::QueryContinueDragEventHandler ^ PreviewQueryContinueDrag;public event System.Windows.QueryContinueDragEventHandler PreviewQueryContinueDrag;member this.PreviewQueryContinueDrag : System.Windows.QueryContinueDragEventHandler Public Custom Event PreviewQueryContinueDrag As QueryContinueDragEventHandler 事件類型
備註
此 PreviewQueryContinueDrag 事件可讓拖曳來源宣告是否應取消拖放作業。The PreviewQueryContinueDrag event enables the drag source to declare whether the drag-and-drop operation should be canceled.
此事件 DragDrop.PreviewQueryContinueDrag 會為這個類別建立附加事件的別名，因此 PreviewQueryContinueDrag 當 UIElement 繼承為基底專案時，它就是類別成員清單的一部分。This event creates an alias for the DragDrop.PreviewQueryContinueDrag attached event for this class, so that PreviewQueryContinueDrag is part of the class members list when UIElement is inherited as a base element. 附加至事件的事件處理常式 PreviewQueryContinueDrag 會附加至基礎 DragDrop.PreviewQueryContinueDrag 附加事件，並接收相同的事件資料實例。Event handlers that are attached to the PreviewQueryContinueDrag event are attached to the underlying DragDrop.PreviewQueryContinueDrag attached event and receive the same event data instance.
路由事件資訊Routed Event Information
| 識別碼欄位Identifier field | PreviewQueryContinueDragEvent |
| 路由策略Routing strategy | 隧道Tunneling |
| 代理人Delegate | QueryContinueDragEventHandler |
對應的反升事件為 QueryContinueDrag 。The corresponding bubbling event is QueryContinueDrag.
OnPreviewQueryContinueDrag在衍生類別中覆寫以執行這個事件的類別處理。Override OnPreviewQueryContinueDrag to implement class handling for this event in derived classes.