ListView.ItemDrag ListView.ItemDrag ListView.ItemDrag ListView.ItemDrag Event

定义

在用户开始拖动项时发生。Occurs when the user begins dragging an item.

public:
 event System::Windows::Forms::ItemDragEventHandler ^ ItemDrag;
public event System.Windows.Forms.ItemDragEventHandler ItemDrag;
member this.ItemDrag : System.Windows.Forms.ItemDragEventHandler 
Public Custom Event ItemDrag As ItemDragEventHandler 

示例

下面的代码示例演示如何使用此成员。The following code example demonstrates the use of this member. 在此示例中, 事件处理程序报告ItemDrag事件的发生。In the example, an event handler reports on the occurrence of the ItemDrag event. 此报表可帮助你了解何时发生事件, 并可帮助你进行调试。This report helps you to learn when the event occurs and can assist you in debugging. 若要报告多个事件或频繁发生的事件, 请考虑MessageBox.ShowConsole.WriteLine消息替换为多行或将TextBox其追加到多行。To report on multiple events or on events that occur frequently, consider replacing MessageBox.Show with Console.WriteLine or appending the message to a multiline TextBox.

若要运行示例代码, 请将其粘贴到包含名为ListView ListView1的类型的实例的项目中。To run the example code, paste it into a project that contains an instance of type ListView named ListView1. 然后, 确保事件处理程序与ItemDrag事件相关联。Then ensure that the event handler is associated with the ItemDrag event.

private void ListView1_ItemDrag(Object sender, ItemDragEventArgs e) {

System.Text.StringBuilder messageBoxCS = new System.Text.StringBuilder();
messageBoxCS.AppendFormat("{0} = {1}", "Button", e.Button );
messageBoxCS.AppendLine();
messageBoxCS.AppendFormat("{0} = {1}", "Item", e.Item );
messageBoxCS.AppendLine();
MessageBox.Show(messageBoxCS.ToString(), "ItemDrag Event" );
}
Private Sub ListView1_ItemDrag(sender as Object, e as ItemDragEventArgs) _ 
     Handles ListView1.ItemDrag

    Dim messageBoxVB as New System.Text.StringBuilder()
    messageBoxVB.AppendFormat("{0} = {1}", "Button", e.Button)
    messageBoxVB.AppendLine()
    messageBoxVB.AppendFormat("{0} = {1}", "Item", e.Item)
    messageBoxVB.AppendLine()
    MessageBox.Show(messageBoxVB.ToString(),"ItemDrag Event")

End Sub

注解

ItemDrag用户开始拖动某个项时发生该事件。The ItemDrag event occurs when the user begins dragging an item. 通常, ItemDrag事件的事件处理程序会通过Control.DoDragDrop调用方法来执行拖动任务。Typically the event handler for the ItemDrag event performs the task of dragging by calling the Control.DoDragDrop method. 你可以使用此事件来执行将项拖入和移出应用程序ListView控件所需的任务。You can use this event to perform the tasks necessary to drag items into and out of your application's ListView control.

有关处理事件的详细信息, 请参阅处理和引发事件For more information about handling events, see Handling and Raising Events.

适用于

另请参阅