Dispatcher.CheckAccess Method

Microsoft Silverlight will reach end of support after October 2021. Learn more.

Determines whether the calling thread is the thread associated with this Dispatcher.

Namespace:  System.Windows.Threading
Assembly:  System.Windows (in System.Windows.dll)


Public Function CheckAccess As Boolean
public bool CheckAccess()

Return Value

Type: System.Boolean
true if the calling thread is the thread associated with this Dispatcher; otherwise, false.


The following code example demonstrates how to use this method.

Private Delegate Sub AddTextDelegate(ByVal p As Panel, ByVal text As String)

Private Sub AddText(ByVal p As Panel, ByVal text As String)
    Dim t As New TextBlock
    t.Text = text
End Sub

Private Sub TestBeginInvokeWithParameters(ByVal p As Panel)
    If p.Dispatcher.CheckAccess() _
        Then AddText(p, "Added directly.") _
        Else p.Dispatcher.BeginInvoke(New AddTextDelegate( _
            AddressOf AddText), p, "Added by Dispatcher.")
End Sub
private delegate void AddTextDelegate(Panel p, String text);

private void AddText(Panel p, String text)
    p.Children.Add(new TextBlock { Text = text });

private void TestBeginInvokeWithParameters(Panel p)
    if (p.Dispatcher.CheckAccess()) AddText(p, "Added directly.");
    else p.Dispatcher.BeginInvoke(
        new AddTextDelegate(AddText), p, "Added by Dispatcher.");

Version Information


Supported in: 5, 4, 3

Silverlight for Windows Phone

Supported in: Windows Phone OS 7.1, Windows Phone OS 7.0


For a list of the operating systems and browsers that are supported by Silverlight, see Supported Operating Systems and Browsers.