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AutomationElement.Cached Vlastnost

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Definice

Obor názvů:
System.Windows.Automation
Sestavení:
UIAutomationClient.dll

Získá hodnoty vlastnosti model UI Automation uložené v mezipaměti pro tento AutomationElement objekt.

public:
 property System::Windows::Automation::AutomationElement::AutomationElementInformation Cached { System::Windows::Automation::AutomationElement::AutomationElementInformation get(); };
public System.Windows.Automation.AutomationElement.AutomationElementInformation Cached { get; }
member this.Cached : System.Windows.Automation.AutomationElement.AutomationElementInformation
Public ReadOnly Property Cached As AutomationElement.AutomationElementInformation

Hodnota vlastnosti

AutomationElement.AutomationElementInformation

Struktura obsahující hodnoty vlastnosti uložené v mezipaměti pro AutomationElement.

Výjimky

InvalidOperationException

Neexistují žádné vlastnosti uložené v mezipaměti.

ElementNotAvailableException

Uživatelské rozhraní již AutomationElement neexistuje.

Příklady

Následující příklad ukazuje, jak Name lze vlastnost uložit do mezipaměti a pak ji načíst pomocí Cached vlastnosti.

/// <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

Poznámky

Přístupové objekty pro vlastnosti model UI Automation jsou reprezentovány jako vlastnosti struktury vrácené Cached. Nemusíte načítat strukturu; k jeho členům můžete přistupovat přímo, jak je znázorněno v následujícím příkladu. Konkrétní informace o dostupných vlastnostech a jejich použití naleznete v tématu AutomationElement.AutomationElementInformation.

Chcete-li získat aktuální hodnotu model UI Automation vlastnosti pro tento prvek použijte Current vlastnost.

Platí pro

Viz také