InvokePattern.Invoke Method

Reference

Definition

Namespace:: System.Windows.Automation

Assembly:: UIAutomationClient.dll

Important

Some information relates to prerelease product that may be substantially modified before it’s released. Microsoft makes no warranties, express or implied, with respect to the information provided here.

Sends a request to activate a control and initiate its single, unambiguous action.

public:
 void Invoke();

public void Invoke ();

member this.Invoke : unit -> unit

Public Sub Invoke ()

Exceptions

InvalidOperationException

The element does not support the InvokePattern control pattern or is hidden or blocked.

ElementNotEnabledException

The element is not enabled. Can be raised when a UI Automation provider has implemented its own handling of the IsEnabled property.

Examples

In the following example an InvokePattern control pattern is obtained from a control and the Invoke method is called.

///--------------------------------------------------------------------
/// <summary>
/// Obtains an InvokePattern control pattern from a control
/// and calls the InvokePattern.Invoke() method on the control.
/// </summary>
/// <param name="targetControl">
/// The control of interest.
/// </param>
///--------------------------------------------------------------------
private void InvokeControl(AutomationElement targetControl)
{
    InvokePattern invokePattern = null;

    try
    {
        invokePattern =
            targetControl.GetCurrentPattern(InvokePattern.Pattern)
            as InvokePattern;
    }
    catch (ElementNotEnabledException)
    {
        // Object is not enabled
        return;
    }
    catch (InvalidOperationException)
    {
        // object doesn't support the InvokePattern control pattern
        return;
    }

    invokePattern.Invoke();
}

'''--------------------------------------------------------------------
''' <summary>
''' Obtains an InvokePattern control pattern from a control
''' and calls the InvokePattern.Invoke() method on the control.
''' </summary>
''' <param name="targetControl">
''' The control of interest.
''' </param>
'''--------------------------------------------------------------------
Private Sub InvokeControl(ByVal targetControl As AutomationElement) 
    Dim invokePattern As InvokePattern = Nothing
    
    Try
        invokePattern = _
        DirectCast(targetControl.GetCurrentPattern(invokePattern.Pattern), _
        InvokePattern)
    Catch e As ElementNotEnabledException
        ' Object is not enabled.
        Return
    Catch e As InvalidOperationException
        ' Object doesn't support the InvokePattern control pattern
        Return
    End Try
    
    invokePattern.Invoke()

End Sub

Remarks

Calls to Invoke should return immediately without blocking. However, this behavior is entirely dependent on the Microsoft UI Automation provider implementation. In scenarios where calling Invoke causes a blocking issue (such as a modal dialog) a separate helper thread may be required to call the method.

Applies to

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