Automation.AddAutomationPropertyChangedEventHandler(AutomationElement, TreeScope, AutomationPropertyChangedEventHandler, AutomationProperty[]) Methode

Definition

Registriert eine Methode, die Eigenschaftenänderungsereignisse behandelt.Registers a method that will handle property-changed events.

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())

Parameter

element
AutomationElement

Das Benutzeroberflächenautomatisierungs-Element, dem der Ereignishandler zugeordnet werden soll.The UI Automation element with which to associate the event handler.

scope
TreeScope

Der Umfang der zu behandelnden Elemente, d. h. ob die Ereignisse bei dem Element selbst oder bei über- oder untergeordneten Elementen eintreten.The scope of events to be handled; that is, whether they are on the element itself, or on its ancestors and children.

eventHandler
AutomationPropertyChangedEventHandler

Die Methode, die beim Eintreten des Ereignisses aufgerufen werden soll.The method to call when the event occurs.

properties
AutomationProperty[]

Die Eigenschaften der Benutzeroberflächen Automatisierung, die von Interesse sind.The UI Automation properties of interest.

Beispiele

Der folgende Beispielcode fügt einen Ereignishandler hinzu, der auf eine Änderung im aktivierten Zustand eines angegebenen Elements lauscht.The following example code adds an event handler that listens for a change in the enabled state of a specified element.


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

Hinweise

Das Benutzeroberflächen Element (UI), das vom angegebenen Benutzeroberflächenautomatisierungs-Element angegeben wird, unterstützt möglicherweise nicht die vom-Parameter angegebenen Eigenschaften properties .The user interface (UI) item specified by the supplied UI Automation element might not support the properties specified by the properties parameter.

eventHandler kann eine Instanz der-Methode oder ein Verweis auf die-Methode ( AddressOf in Visual Basic) sein.eventHandler can be an instance of the method, or a reference to the method (AddressOf in Visual Basic).

Gilt für:

Siehe auch