Automation.AddAutomationFocusChangedEventHandler Method

  • Reference

Definition

Namespace:
System.Windows.Automation
Assembly:
UIAutomationClient.dll

Registers a method that will handle focus-changed events.

public:
 static void AddAutomationFocusChangedEventHandler(System::Windows::Automation::AutomationFocusChangedEventHandler ^ eventHandler);
public static void AddAutomationFocusChangedEventHandler (System.Windows.Automation.AutomationFocusChangedEventHandler eventHandler);
static member AddAutomationFocusChangedEventHandler : System.Windows.Automation.AutomationFocusChangedEventHandler -> unit
Public Shared Sub AddAutomationFocusChangedEventHandler (eventHandler As AutomationFocusChangedEventHandler)

Parameters

eventHandler
AutomationFocusChangedEventHandler

The method to call when the event occurs.

Examples

The following example shows this method being used to add an event handler for focus changes.

AutomationFocusChangedEventHandler focusHandler = null;

/// <summary>
/// Create an event handler and register it.
/// </summary>
public void SubscribeToFocusChange()
{
    focusHandler = new AutomationFocusChangedEventHandler(OnFocusChange);
    Automation.AddAutomationFocusChangedEventHandler(focusHandler);
}

/// <summary>
/// Handle the event.
/// </summary>
/// <param name="src">Object that raised the event.</param>
/// <param name="e">Event arguments.</param>
private void OnFocusChange(object src, AutomationFocusChangedEventArgs e)
{
    // TODO Add event handling code.
    // The arguments tell you which elements have lost and received focus.
}

/// <summary>
/// Cancel subscription to the event.
/// </summary>
public void UnsubscribeFocusChange()
{
    if (focusHandler != null)
    {
        Automation.RemoveAutomationFocusChangedEventHandler(focusHandler);
    }
}

Private focusHandler As AutomationFocusChangedEventHandler = Nothing


''' <summary>
''' Create an event handler and register it.
''' </summary>
Public Sub SubscribeToFocusChange()
    focusHandler = New AutomationFocusChangedEventHandler(AddressOf OnFocusChange)
    Automation.AddAutomationFocusChangedEventHandler(focusHandler)

End Sub


''' <summary>
''' Handle the event.
''' </summary>
''' <param name="src">Object that raised the event.</param>
''' <param name="e">Event arguments.</param>
Private Sub OnFocusChange(ByVal src As Object, ByVal e As AutomationFocusChangedEventArgs)

End Sub

' TODO Add event handling code.
' The arguments tell you which elements have lost and received focus.

''' <summary>
''' Cancel subscription to the event.
''' </summary>
Public Sub UnsubscribeFocusChange()
    If (focusHandler IsNot Nothing) Then
        Automation.RemoveAutomationFocusChangedEventHandler(focusHandler)
    End If

End Sub

Remarks

Focus-changed events are system-wide; you cannot set a narrower scope.

eventHandler can be an instance of the method, or a reference to the method (AddressOf in Visual Basic).

Applies to

See also