Automation.AddAutomationFocusChangedEventHandler 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.

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

Product	Versions
.NET Framework	3.0, 3.5, 4.0, 4.5, 4.5.1, 4.5.2, 4.6, 4.6.1, 4.6.2, 4.7, 4.7.1, 4.7.2, 4.8, 4.8.1
Windows Desktop	3.0, 3.1, 5, 6, 7, 8, 9, 10

Share via