語言

ItemCollection.Clear 方法

定義

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

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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

它 ItemCollection 進入 ItemsSource 模式。 （當屬性 ItemsSource 設定完成後，集合 Items 將改為唯讀且大小固定。）

範例

以下範例展示了如何使用此方法。 在範例中， sbar 是一個 StatusBar 控制點，而 則是一個 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

適用於

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