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CacheRequest.TreeScope Eigenschaft

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Definition

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

Ruft einen Wert ab, der angibt, ob das Zwischenspeichern nur für den Stamm der Teilstruktur oder auch für untergeordnete Elemente oder Nachfolgerelemente erfolgt, oder legt diesen fest.

public:
 property System::Windows::Automation::TreeScope TreeScope { System::Windows::Automation::TreeScope get(); void set(System::Windows::Automation::TreeScope value); };
public System.Windows.Automation.TreeScope TreeScope { get; set; }
member this.TreeScope : System.Windows.Automation.TreeScope with get, set
Public Property TreeScope As TreeScope

Eigenschaftswert

TreeScope

Ein oder mehrere Elemente von Element, Children, Descendants oder Subtree. Der Standardwert ist Element.

Ausnahmen

ArgumentException

Es wurde versucht, die Eigenschaft auf Parent oder Ancestors festzulegen.

Beispiele

Im folgenden Beispiel wird ein Listenfeldelement aus dem übergeordneten Fensterelement abgerufen, während ein CacheRequest aktiv ist und TreeScope ist Children. Die angegebenen Eigenschaften der untergeordneten Elemente (d. h. die Listenelemente) werden im Cache gespeichert und können aus dem CachedChildren Listenfeld abgerufen werden.

/// <summary>
/// Gets a list box element and caches the Name property of its children (the list items).
/// </summary>
/// <param name="elementMain">The UI Automation element for the parent window.</param>
void CachePropertiesWithScope(AutomationElement elementMain)
{
    AutomationElement elementList;

    // Set up the CacheRequest.
    CacheRequest cacheRequest = new CacheRequest();
    cacheRequest.Add(AutomationElement.NameProperty);
    cacheRequest.TreeScope = TreeScope.Element | TreeScope.Children;

    // Activate the CacheRequest and get the element. Note that the scope of the CacheRequest
    // is in relation to the object being retrieved: the list box and its children are 
    // cached, not the main window and its children.
    using (cacheRequest.Activate())
    {
        // Load the list element and cache the specified properties for its descendants.
        Condition cond = new PropertyCondition(AutomationElement.ControlTypeProperty, ControlType.List);
        elementList = elementMain.FindFirst(TreeScope.Children, cond);
    }
    if (elementList == null) return;

    // The following illustrates that the children of the list are in the cache.
    foreach (AutomationElement listItem in elementList.CachedChildren)
    {
        Console.WriteLine(listItem.Cached.Name);
    }

    // The following call raises an exception, because the IsEnabled property was not cached.
    /*** Console.WriteLine(listItem.Cached.IsEnabled); ***/

    // The following illustrates that because the list box itself was cached, it is now
    // available as the CachedParent of each list item.
    AutomationElement child = elementList.CachedChildren[0];
    Console.WriteLine(child.CachedParent.Cached.Name);
}

''' <summary>
''' Gets a list box element and caches the Name property of its children (the list items).
''' </summary>
''' <param name="elementMain">The UI Automation element for the parent window.</param>
Sub CachePropertiesWithScope(ByVal elementMain As AutomationElement)
    Dim elementList As AutomationElement

    ' Set up the CacheRequest.
    Dim cacheRequest As New CacheRequest()
    cacheRequest.Add(AutomationElement.NameProperty)
    cacheRequest.TreeScope = TreeScope.Element Or TreeScope.Children

    ' Activate the CacheRequest and get the element. Note that the scope of the CacheRequest
    ' is in relation to the object being retrieved: the list box and its children are 
    ' cached, not the main window and its children.
    Using cacheRequest.Activate()
        ' Load the list element and cache the specified properties for its descendants.
        Dim myCondition As New PropertyCondition(AutomationElement.ControlTypeProperty, ControlType.List)
        elementList = elementMain.FindFirst(TreeScope.Children, myCondition)

        If elementList Is Nothing Then
            Return
        End If

        ' The following illustrates that the children of the list are in the cache.
        Dim listItem As AutomationElement
        For Each listItem In elementList.CachedChildren
            Console.WriteLine(listItem.Cached.Name)
        Next listItem

        ' The following call raises an exception, because the IsEnabled property was not cached.
        '** Console.WriteLine(listItem.Cached.IsEnabled) **

        ' The following illustrates that because the list box itself was cached, it is now
        ' available as the CachedParent of each list item.
        Dim child As AutomationElement = elementList.CachedChildren(0)
        Console.WriteLine(child.CachedParent.Cached.Name)
    End Using
End Sub

Hinweise

Der Bereich der Zwischenspeicherung bezieht sich auf das oder die abgerufenen Objekte, nicht auf das Objekt, für das FindFirst oder FindAll aufgerufen wird. Siehe das Beispiel.

Gilt für:

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