Sottoscrivere gli eventi di automazione interfaccia utente
Nota
Questa documentazione è destinata agli sviluppatori .NET Framework che desiderano utilizzare le classi di UI Automation gestite definite nello spazio dei nomi System.Windows.Automation. Per informazioni aggiornate su UI Automation, vedere API di automazione di Windows: UI Automation.
Questo argomento illustra come sottoscrivere gli eventi generati dai provider di automazione interfaccia utente.
Esempio 1
Il codice di esempio seguente registra un gestore eventi per l'evento che viene generato quando viene richiamato un controllo, ad esempio un pulsante, e lo rimuove quando il form dell'applicazione viene chiuso. L'evento viene identificato da un oggetto AutomationEvent passato come parametro a AddAutomationEventHandler.
// Member variables.
AutomationElement ElementSubscribeButton;
AutomationEventHandler UIAeventHandler;
/// <summary>
/// Register an event handler for InvokedEvent on the specified element.
/// </summary>
/// <param name="elementButton">The automation element.</param>
public void SubscribeToInvoke(AutomationElement elementButton)
{
if (elementButton != null)
{
Automation.AddAutomationEventHandler(InvokePattern.InvokedEvent,
elementButton, TreeScope.Element,
UIAeventHandler = new AutomationEventHandler(OnUIAutomationEvent));
ElementSubscribeButton = elementButton;
}
}
/// <summary>
/// AutomationEventHandler delegate.
/// </summary>
/// <param name="src">Object that raised the event.</param>
/// <param name="e">Event arguments.</param>
private void OnUIAutomationEvent(object src, AutomationEventArgs e)
{
// Make sure the element still exists. Elements such as tooltips
// can disappear before the event is processed.
AutomationElement sourceElement;
try
{
sourceElement = src as AutomationElement;
}
catch (ElementNotAvailableException)
{
return;
}
if (e.EventId == InvokePattern.InvokedEvent)
{
// TODO Add handling code.
}
else
{
// TODO Handle any other events that have been subscribed to.
}
}
private void ShutdownUIA()
{
if (UIAeventHandler != null)
{
Automation.RemoveAutomationEventHandler(InvokePattern.InvokedEvent,
ElementSubscribeButton, UIAeventHandler);
}
}
' Member variables.
Private ElementSubscribeButton As AutomationElement
Private UIAeventHandler As AutomationEventHandler
''' <summary>
''' Register an event handler for InvokedEvent on the specified element.
''' </summary>
''' <param name="elementButton">The automation element.</param>
Public Sub SubscribeToInvoke(ByVal elementButton As AutomationElement)
If (elementButton IsNot Nothing) Then
UIAeventHandler = New AutomationEventHandler(AddressOf OnUIAutomationEvent)
Automation.AddAutomationEventHandler(InvokePattern.InvokedEvent, elementButton, _
TreeScope.Element, UIAeventHandler)
ElementSubscribeButton = elementButton
End If
End Sub
''' <summary>
''' AutomationEventHandler delegate.
''' </summary>
''' <param name="src">Object that raised the event.</param>
''' <param name="e">Event arguments.</param>
Private Sub OnUIAutomationEvent(ByVal src As Object, ByVal e As AutomationEventArgs)
' Make sure the element still exists. Elements such as tooltips can disappear
' before the event is processed.
Dim sourceElement As AutomationElement
Try
sourceElement = DirectCast(src, AutomationElement)
Catch ex As ElementNotAvailableException
Exit Sub
End Try
If e.EventId Is InvokePattern.InvokedEvent Then
' TODO Add handling code.
Else
End If
' TODO Handle any other events that have been subscribed to.
Console.WriteLine("Event: " & e.EventId.ProgrammaticName)
End Sub
Private Sub ShutdownUIA()
If (UIAeventHandler IsNot Nothing) Then
Automation.RemoveAutomationEventHandler(InvokePattern.InvokedEvent, ElementSubscribeButton, UIAeventHandler)
End If
End Sub
Esempio 2
L'esempio seguente illustra come usare Microsoft UI Automation per sottoscrivere un evento generato quando lo stato attivo cambia. Il gestore eventi non è registrato in un metodo che può essere chiamato all'arresto dell'applicazione o quando la notifica degli eventi dell'interfaccia utente non è più necessaria.
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