Lenguaje

AutomationPropertyChangedEventArgs(AutomationProperty, Object, Object) Constructor

Definición

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

Inicializa una nueva instancia de la clase AutomationPropertyChangedEventArgs.

public:
 AutomationPropertyChangedEventArgs(System::Windows::Automation::AutomationProperty ^ property, System::Object ^ oldValue, System::Object ^ newValue);
public AutomationPropertyChangedEventArgs(System.Windows.Automation.AutomationProperty property, object oldValue, object newValue);
new System.Windows.Automation.AutomationPropertyChangedEventArgs : System.Windows.Automation.AutomationProperty * obj * obj -> System.Windows.Automation.AutomationPropertyChangedEventArgs
Public Sub New (property As AutomationProperty, oldValue As Object, newValue As Object)

Parámetros

property
AutomationProperty

Identificador de la propiedad que ha cambiado.

oldValue
Object

Valor anterior de la propiedad .

newValue
Object

Valor nuevo de la propiedad.

Ejemplos

En el ejemplo siguiente se construye y genera un evento cuando una propiedad ha cambiado.

/// <summary>
/// Raises an event when the IsEnabled property on a control is changed.
/// </summary>
/// <param name="provider">The UI Automation provider for the control.</param>
/// <param name="newValue">The current enabled state.</param>
private void RaiseEnabledEvent(IRawElementProviderSimple provider, bool newValue)
{
    if (AutomationInteropProvider.ClientsAreListening)
    {
        AutomationPropertyChangedEventArgs args =
            new AutomationPropertyChangedEventArgs(AutomationElement.IsEnabledProperty,
                !newValue, newValue);
        AutomationInteropProvider.RaiseAutomationPropertyChangedEvent(provider, args);
    }
}

''' <summary>
''' Raises an event when the IsEnabled property on a control is changed.
''' </summary>
''' <param name="provider">The UI Automation provider for the control.</param>
''' <param name="newValue">The current enabled state.</param>
Private Sub RaiseEnabledEvent(ByVal provider As IRawElementProviderSimple, ByVal newValue As Boolean) 
    If AutomationInteropProvider.ClientsAreListening Then
        Dim args As New AutomationPropertyChangedEventArgs(AutomationElement.IsEnabledProperty, Not newValue, newValue)
        AutomationInteropProvider.RaiseAutomationPropertyChangedEvent(provider, args)
    End If

End Sub

Comentarios

oldValue puede ser null (Nothing en Visual Basic) si el valor anterior no está disponible fácilmente.

Se aplica a