ComboBox.DropDownOpened 事件

定義

命名空間:

System.Windows.Controls

組件:

PresentationFramework.dll

發生於下拉式方塊的下拉式清單開啟時。

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

下列範例示範如何指派事件處理常式並處理 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 == true)
    {
        cb.Text = "Combo box opened";
    }
}

void OnDropDownClosed(object sender, EventArgs e)
{
    if (cb.IsDropDownOpen == false)
    {
        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