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Automation.RemoveAutomationPropertyChangedEventHandler Methode

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Definition

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

Entfernt den angegebenen Ereignishandler für Eigenschaftenänderungen.

public:
 static void RemoveAutomationPropertyChangedEventHandler(System::Windows::Automation::AutomationElement ^ element, System::Windows::Automation::AutomationPropertyChangedEventHandler ^ eventHandler);
public static void RemoveAutomationPropertyChangedEventHandler (System.Windows.Automation.AutomationElement element, System.Windows.Automation.AutomationPropertyChangedEventHandler eventHandler);
static member RemoveAutomationPropertyChangedEventHandler : System.Windows.Automation.AutomationElement * System.Windows.Automation.AutomationPropertyChangedEventHandler -> unit
Public Shared Sub RemoveAutomationPropertyChangedEventHandler (element As AutomationElement, eventHandler As AutomationPropertyChangedEventHandler)

Parameter

element
AutomationElement

Das Benutzeroberflächenautomatisierung Element, aus dem der Ereignishandler entfernt werden soll.

eventHandler
AutomationPropertyChangedEventHandler

Eine Handlermethode, die für das angegebene Benutzeroberflächenautomatisierung-Element übergeben AddAutomationPropertyChangedEventHandler(AutomationElement, TreeScope, AutomationPropertyChangedEventHandler, AutomationProperty[]) wurde.

Hinweise

Der folgende Beispielcode zeigt einen Eigenschaft geänderten Ereignishandler, der hinzugefügt und entfernt wird.


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

Gilt für

Siehe auch