ItemCollection.Clear 方法

定义

命名空间:

System.Windows.Controls

程序集:

PresentationFramework.dll

清除集合并释放集合中当前所有项的引用。

public:
 virtual void Clear();

public void Clear ();

abstract member Clear : unit -> unit
override this.Clear : unit -> unit

Public Sub Clear ()

实现

Clear()

例外

InvalidOperationException

ItemCollection 处于 ItemsSource 模式。 （当设置 ItemsSource 属性时，Items 集合将是只读的，且具有固定大小。）

示例

以下示例演示如何使用此方法。 在此示例中， sbar 是一个 StatusBar 控件，即一个 ItemsControl控件。

private void MakeProgressBar(object sender, RoutedEventArgs e)
{
    sbar.Items.Clear();
    TextBlock txtb = new TextBlock();
    txtb.Text = "Progress of download.";
    sbar.Items.Add(txtb);
    ProgressBar progressbar = new ProgressBar();
    progressbar.Width = 100;
    progressbar.Height = 20;
    Duration duration = new Duration(TimeSpan.FromSeconds(5));
    DoubleAnimation doubleanimation =
                               new DoubleAnimation(100.0, duration);
    progressbar.BeginAnimation(ProgressBar.ValueProperty,
                               doubleanimation);
    ToolTip ttprogbar = new ToolTip();
    ttprogbar.Content = "Shows the progress of a download.";
    progressbar.ToolTip = (ttprogbar);
    sbar.Items.Add(progressbar);
}

Private Sub MakeProgressBar(ByVal sender As Object, ByVal e As RoutedEventArgs)
    sbar.Items.Clear()
    Dim txtb As New TextBlock()
    txtb.Text = "Progress of download."
    sbar.Items.Add(txtb)
    Dim progressbar As New ProgressBar()
    progressbar.Width = 100
    progressbar.Height = 20
    Dim duration As New Duration(TimeSpan.FromSeconds(5))
    Dim doubleanimation As New DoubleAnimation(100.0, duration)
    progressbar.BeginAnimation(ProgressBar.ValueProperty, doubleanimation)
    Dim ttprogbar As New ToolTip()
    ttprogbar.Content = "Shows the progress of a download."
    progressbar.ToolTip = (ttprogbar)
    sbar.Items.Add(progressbar)
End Sub

另请参阅

• ItemsControl