語言

ComboBox.DropDownOpened 活動

定義

命名空間:
System.Windows.Controls
組件:
PresentationFramework.dll

當連擊框的下拉選單打開時發生。

public:
 event EventHandler ^ DropDownOpened;
public event EventHandler DropDownOpened;
member this.DropDownOpened : EventHandler 
Public Custom Event DropDownOpened As EventHandler

事件類型

EventHandler

範例

以下範例說明如何指派事件處理器並處理 DropDownOpened 和 DropDownClosed 事件。

<ComboBox Name="cb" StaysOpenOnEdit="true" IsEditable="true" DropDownOpened="OnDropDownOpened" 
        DropDownClosed="OnDropDownClosed">

void OnDropDownOpened(object sender, EventArgs e)
{
    if (cb.IsDropDownOpen)
    {
        cb.Text = "Combo box opened";
    }
}

void OnDropDownClosed(object sender, EventArgs e)
{
    if (!cb.IsDropDownOpen)
    {
        cb.Text = "Combo box closed";
    }
}

Private Sub OnDropDownOpened(ByVal Sender As Object, ByVal e As EventArgs)

    If (cb.IsDropDownOpen = True) Then
        cb.Text = "Combo box opened"
    End If

End Sub

Private Sub OnDropDownClosed(ByVal Sender As Object, ByVal e As EventArgs)

    If (cb.IsDropDownOpen = False) Then
        cb.Text = "Combo box closed"
    End If

End Sub

適用於