CacheRequest.TreeScope Propriété

Définition

Obtient ou définit une valeur qui spécifie si la mise en cache s'effectue uniquement pour la racine du sous-arbre ou également pour ses enfants ou descendants.Gets or sets a value that specifies whether caching is done only for the root of the subtree, or also for its children or descendants.

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

Valeur de propriété

Une ou plusieurs des valeurs Element, Children, Descendants ou Subtree.One or more of Element, Children, Descendants, or Subtree. La valeur par défaut est Element.The default value is Element.

Exceptions

Une tentative a été faite d'affecter Parent ou Ancestors à la propriété.An attempt was made to set the property to Parent or Ancestors.

Exemples

Dans l’exemple suivant, un élément de zone de liste est obtenu à partir de l’élément CacheRequest de fenêtre parente Childrenalors qu’un est actif et TreeScope que est.In the following example, a list box element is obtained from the parent window element while a CacheRequest is active and TreeScope is Children. Les propriétés spécifiées des éléments enfants (autrement dit, les éléments de liste) sont stockées dans le cache et peuvent être récupérées CachedChildren à partir du de la zone de liste.The specified properties of the child elements (that is, the list items) are stored in the cache and can be retrieved from the CachedChildren of the list box.

/// <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

Remarques

La portée de la mise en cache est liée à l’objet ou aux objets récupérés, et non pas par rapport à FindFirst l' FindAll objet sur lequel ou est appelé.The scope of caching is in relation to the object or objects being fetched, not in relation to the object on which FindFirst or FindAll is called. Consultez l’exemple.See the example.

S’applique à

Voir aussi