AutomationElement.CachedChildren Özellik

Tanım

Ad Alanı:

System.Windows.Automation

Bütünleştirilmiş Kod:

UIAutomationClient.dll

Bu AutomationElementöğesinin önbelleğe alınmış alt öğelerini alır.

public:
 property System::Windows::Automation::AutomationElementCollection ^ CachedChildren { System::Windows::Automation::AutomationElementCollection ^ get(); };

public System.Windows.Automation.AutomationElementCollection CachedChildren { get; }

member this.CachedChildren : System.Windows.Automation.AutomationElementCollection

Public ReadOnly Property CachedChildren As AutomationElementCollection

Özellik Değeri

AutomationElementCollection

Alt öğelerin koleksiyonu. Öğede alt öğe yoksa bu koleksiyon boş olabilir.

Özel durumlar

ElementNotAvailableException

için AutomationElement kullanıcı arabirimi artık yok.

InvalidOperationException

Bu öğenin alt öğelerini önbelleğe almak için istek yapılmadı.

Örnekler

Aşağıdaki örnekte, bir etkin ve TreeScopeChildrenolduğunda üst pencere öğesinden bir CacheRequest liste kutusu öğesi alınır. Alt öğelerin belirtilen özellikleri (yani liste öğeleri) önbellekte depolanır ve liste kutusundan CachedChildren alınabilir.

/// <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

Açıklamalar

Döndürülen koleksiyonun görünümü, bu AutomationElement nesne elde edildiğinde etkin olan koşuluna CacheRequest göre TreeFilter belirlenir.

Alt öğeler yalnızca dahil Subtreeedilen , Childrenveya Descendantskapsamı CacheRequest ise önbelleğe alınır.

CacheRequest Belirtilen alt öğeler bu düzeyde önbelleğe alındıysa ancak alt öğe yoksa, bu özelliğin değeri 0'dır. Ancak, bu düzeyde alt önbelleğe almak için istek yapılmadıysa, özelliği alma girişimi bir özel durum oluşturur.

Ayrıca bkz.

• UI Otomasyonda Önbelleğe Alma