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Automation.AddAutomationPropertyChangedEventHandler Método

  • Referencia

Definición

Espacio de nombres:
System.Windows.Automation
Ensamblado:
UIAutomationClient.dll

Registra un método que controla los eventos de cambio de propiedad.

public:
 static void AddAutomationPropertyChangedEventHandler(System::Windows::Automation::AutomationElement ^ element, System::Windows::Automation::TreeScope scope, System::Windows::Automation::AutomationPropertyChangedEventHandler ^ eventHandler, ... cli::array <System::Windows::Automation::AutomationProperty ^> ^ properties);
public static void AddAutomationPropertyChangedEventHandler (System.Windows.Automation.AutomationElement element, System.Windows.Automation.TreeScope scope, System.Windows.Automation.AutomationPropertyChangedEventHandler eventHandler, params System.Windows.Automation.AutomationProperty[] properties);
static member AddAutomationPropertyChangedEventHandler : System.Windows.Automation.AutomationElement * System.Windows.Automation.TreeScope * System.Windows.Automation.AutomationPropertyChangedEventHandler * System.Windows.Automation.AutomationProperty[] -> unit
Public Shared Sub AddAutomationPropertyChangedEventHandler (element As AutomationElement, scope As TreeScope, eventHandler As AutomationPropertyChangedEventHandler, ParamArray properties As AutomationProperty())

Parámetros

element
AutomationElement

Elemento Automatización de la interfaz de usuario al que se va a asociar el controlador de eventos.

scope
TreeScope

Ámbito de eventos que se va a controlar; es decir, si se va a controlar el propio elemento o sus antecesores y elementos secundarios.

eventHandler
AutomationPropertyChangedEventHandler

Método al que se debe llamar cuando se produzca el evento.

properties
AutomationProperty[]

Propiedades Automatización de la interfaz de usuario de interés.

Ejemplos

En el código de ejemplo siguiente se agrega un controlador de eventos que escucha un cambio en el estado habilitado de un elemento especificado.


AutomationPropertyChangedEventHandler propChangeHandler;
/// <summary>
/// Adds a handler for property-changed event; in particular, a change in the enabled state.
/// </summary>
/// <param name="element">The UI Automation element whose state is being monitored.</param>
public void SubscribePropertyChange(AutomationElement element)
{
    Automation.AddAutomationPropertyChangedEventHandler(element, 
        TreeScope.Element, 
        propChangeHandler = new AutomationPropertyChangedEventHandler(OnPropertyChange),
        AutomationElement.IsEnabledProperty);
}

/// <summary>
/// Handler for property changes.
/// </summary>
/// <param name="src">The source whose properties changed.</param>
/// <param name="e">Event arguments.</param>
private void OnPropertyChange(object src, AutomationPropertyChangedEventArgs e)
{
    AutomationElement sourceElement = src as AutomationElement;
    if (e.Property == AutomationElement.IsEnabledProperty)
    {
        bool enabled = (bool)e.NewValue;
        // TODO: Do something with the new value. 
        // The element that raised the event can be identified by its runtime ID property.
    }
    else
    { 
        // TODO: Handle other property-changed events.
    }
}

public void UnsubscribePropertyChange(AutomationElement element)
{
    if (propChangeHandler != null)
    {
        Automation.RemoveAutomationPropertyChangedEventHandler(element, propChangeHandler);
    }
}


Dim propChangeHandler As AutomationPropertyChangedEventHandler

''' <summary>
''' Adds a handler for property-changed event; in particular, a change in the enabled state.
''' </summary>
''' <param name="element">The UI Automation element whose state is being monitored.</param>
Public Sub SubscribePropertyChange(ByVal element As AutomationElement)
    propChangeHandler = _
        New AutomationPropertyChangedEventHandler(AddressOf OnPropertyChange)
    Automation.AddAutomationPropertyChangedEventHandler(element, TreeScope.Element, _
        propChangeHandler, AutomationElement.IsEnabledProperty)

End Sub



''' <summary>
''' Handler for property changes.
''' </summary>
''' <param name="src">The source whose properties changed.</param>
''' <param name="e">Event arguments.</param>
Private Sub OnPropertyChange(ByVal src As Object, ByVal e As AutomationPropertyChangedEventArgs) 
    Dim sourceElement As AutomationElement = DirectCast(src, AutomationElement)
    If e.Property Is AutomationElement.IsEnabledProperty Then
        Dim enabled As Boolean = CBool(e.NewValue)
        ' TODO: Do something with the new value. 
        ' The element that raised the event can be identified by its runtime ID property.
    Else
    End If
 ' TODO: Handle other property-changed events.
End Sub


Public Sub UnsubscribePropertyChange(ByVal element As AutomationElement)
    If (propChangeHandler IsNot Nothing) Then
        Automation.RemoveAutomationPropertyChangedEventHandler(element, propChangeHandler)
    End If

End Sub

Comentarios

Es posible que el elemento de interfaz de usuario especificado por el elemento Automatización de la interfaz de usuario proporcionado no admita las propiedades especificadas por el properties parámetro .

eventHandler puede ser una instancia del método o una referencia al método (AddressOf en Visual Basic).

Se aplica a

Consulte también