如何：移除元素的子节点

更新：2007 年 11 月

本示例演示如何使用 Clear 方法移除 UIElementCollection 中的所有元素。

下面的可扩展应用程序标记语言 (XAML) 示例创建一个 TabControl。当用户单击**“Clear Controls”（清除控件）**选项卡时，用 C# 编写的 MouseLeftButtonDown 事件处理程序 ClearButtons 会首先添加四个按钮，之后，在单击新创建的按钮之一时，所有的按钮都将被清除。

示例

Private Sub RemoveButton(ByVal sender As Object, ByVal e As MouseButtonEventArgs)
    If (sp1.Children.IndexOf(btn) >= 0) Or (sp1.Children.IndexOf(btn1) >= 0) Or (sp1.Children.IndexOf(btn2) >= 0) Or (sp1.Children.IndexOf(btn3) >= 0) Then
        sp1.Children.RemoveAt(0)
    End If
End Sub

<TabItem MouseLeftButtonUp="ClearButtons">
<TabItem.Header>Clear Controls</TabItem.Header>
</TabItem>

...

        void ClearButtons(object sender, MouseButtonEventArgs e)
        {
            sp1.Children.Clear();
            btn = new Button();
            btn.Content = "Click to clear";
            sp1.Children.Add(btn);
            btn.Click += (ClearControls);
            btn1 = new Button();
            btn1.Content = "Click to clear";
            sp1.Children.Add(btn1);
            btn1.Click += (ClearControls);
            btn2 = new Button();
            btn2.Content = "Click to clear";
            sp1.Children.Add(btn2);
            btn2.Click += (ClearControls);
            btn3 = new Button();
            btn3.Content = "Click to clear";
            sp1.Children.Add(btn3);
            btn3.Click += (ClearControls);
        }

        void ClearControls(object sender, RoutedEventArgs e)
        {
            sp1.Children.Clear();
        }

该事件处理程序还可以用 Microsoft Visual Basic .NET 来编写。

Private Sub ClearButtons(ByVal sender As Object, ByVal e As MouseButtonEventArgs)
    sp1.Children.Clear()
    btn = New Button()
    btn.Content = "Click to clear"
    sp1.Children.Add(btn)
    AddHandler btn.Click, AddressOf Me.ClearControls
    btn1 = New Button()
    btn1.Content = "Click to clear"
    sp1.Children.Add(btn1)
    AddHandler btn1.Click, AddressOf Me.ClearControls
    btn2 = New Button()
    btn2.Content = "Click to clear"
    sp1.Children.Add(btn2)
    AddHandler btn2.Click, AddressOf Me.ClearControls
    btn3 = New Button()
    btn3.Content = "Click to clear"
    sp1.Children.Add(btn3)
    AddHandler btn3.Click, AddressOf Me.ClearControls
End Sub

Private Sub ClearControls(ByVal sender As Object, ByVal e As RoutedEventArgs)
    sp1.Children.Clear()
End Sub

void ContainsElement(object sender, RoutedEventArgs e)
{
    TextBlock txt1 = new TextBlock();
    sp1.Children.Add(txt1);
    txt1.Text = "This StackPanel contains UIElement btn1: " + sp1.Children.Contains(btn1).ToString();
}

说明：
有关完整的代码示例，请参见元素的用法示例。

请参见

任务

元素的用法示例

参考

UIElementCollection