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TreeView.BeforeSelect 事件

定義

發生於選取樹狀節點之前。

public:
 event System::Windows::Forms::TreeViewCancelEventHandler ^ BeforeSelect;
public event System.Windows.Forms.TreeViewCancelEventHandler BeforeSelect;
public event System.Windows.Forms.TreeViewCancelEventHandler? BeforeSelect;
member this.BeforeSelect : System.Windows.Forms.TreeViewCancelEventHandler 
Public Custom Event BeforeSelect As TreeViewCancelEventHandler 

事件類型

範例

下列程式碼範例示範此成員的使用。 在此範例中,事件處理常式會報告事件發生次數 BeforeSelect 。 此報告可協助您瞭解事件發生的時間,並可協助您進行偵錯。 若要報告多個事件或經常發生的事件,請考慮將 取代 MessageBox.ShowConsole.WriteLine 為 或將訊息附加至多行 TextBox

若要執行範例程式碼,請將它貼到包含名為 TreeView1 之型 TreeView 別實例的專案。 然後,確定事件處理常式與事件相關聯 BeforeSelect

private void TreeView1_BeforeSelect(Object sender, TreeViewCancelEventArgs e) {

System.Text.StringBuilder messageBoxCS = new System.Text.StringBuilder();
messageBoxCS.AppendFormat("{0} = {1}", "Node", e.Node );
messageBoxCS.AppendLine();
messageBoxCS.AppendFormat("{0} = {1}", "Action", e.Action );
messageBoxCS.AppendLine();
messageBoxCS.AppendFormat("{0} = {1}", "Cancel", e.Cancel );
messageBoxCS.AppendLine();
MessageBox.Show(messageBoxCS.ToString(), "BeforeSelect Event" );
}
Private Sub TreeView1_BeforeSelect(sender as Object, e as TreeViewCancelEventArgs) _ 
     Handles TreeView1.BeforeSelect

    Dim messageBoxVB as New System.Text.StringBuilder()
    messageBoxVB.AppendFormat("{0} = {1}", "Node", e.Node)
    messageBoxVB.AppendLine()
    messageBoxVB.AppendFormat("{0} = {1}", "Action", e.Action)
    messageBoxVB.AppendLine()
    messageBoxVB.AppendFormat("{0} = {1}", "Cancel", e.Cancel)
    messageBoxVB.AppendLine()
    MessageBox.Show(messageBoxVB.ToString(),"BeforeSelect Event")

End Sub

備註

如需如何處理事件的詳細資訊,請參閱 處理和引發事件

適用於

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