ItemCollection.Clear 方法

定義

命名空間:

System.Windows.Controls

組件:

PresentationFramework.dll

清除集合並釋放目前集合中所有項目上的參考。

public:
 virtual void Clear();

public void Clear ();

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

Public Sub Clear ()

實作

Clear()

例外狀況

InvalidOperationException

ItemCollection 是 ItemsSource 模式。 (當設定 ItemsSource 屬性時，Items 集合會被設為唯讀且固定大小)。

範例

下列範例示範如何使用這個方法。 在此範例中， sbar 是 控制項 StatusBar ，也就是 ItemsControl 。

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

另請參閱

• ItemsControl