CacheRequest.TreeScope Propiedad
Definición
Importante
Parte de la información hace referencia a la versión preliminar del producto, que puede haberse modificado sustancialmente antes de lanzar la versión definitiva. Microsoft no otorga ninguna garantía, explícita o implícita, con respecto a la información proporcionada aquí.
Obtiene o establece un valor que especifica si el almacenamiento en caché solo se realiza para la raíz del subárbol, o también para sus elementos secundarios o descendientes.
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, setPublic Property TreeScope As TreeScopeValor de propiedad
Uno o varios de Element, Children, Descendantso Subtree. El valor por defecto es Element.
Excepciones
Ejemplos
En el ejemplo siguiente, se obtiene un elemento de cuadro de lista del elemento primario de la ventana mientras está CacheRequest activo y TreeScope es Children. Las propiedades especificadas de los elementos secundarios (es decir, los elementos de lista) se almacenan en la memoria caché y se pueden recuperar del CachedChildren del cuadro de lista.
/// <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
Comentarios
El ámbito del almacenamiento en caché está en relación con el objeto o los objetos que se capturan, no en relación con el objeto en el que FindFirst se llama a o FindAll . Vea el ejemplo.
