CacheRequest.AutomationElementMode Eigenschaft

Definition

Ruft einen Wert ab, der angibt, ob zurückgegebene Elemente vollständige Verweise auf die zugrunde liegende Benutzeroberfläche oder nur zwischengespeicherte Informationen enthalten sollen, oder legt diesen fest.Gets or sets a value that specifies whether returned elements should contain full references to the underlying user interface (UI), or only cached information.

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

Eigenschaftswert

AutomationElementMode

Full , wenn die zurückgegebenen Elemente über einen vollständigen Verweis auf die zugrunde liegende Benutzeroberfläche (UI) verfügen. andernfalls None .Full if the returned elements have a full reference to the underlying user interface (UI); otherwise None.

Beispiele

Im folgenden Beispiel AutomationElementMode wird auf festgelegt None , wobei das Ergebnis ist, dass nur zwischengespeicherte Eigenschaften und Muster für das abgerufene Objekt verfügbar sind.In the following example, AutomationElementMode is set to None, with the result that only cached properties and patterns are available for the retrieved object.

/// <summary>
/// Caches and retrieves properties for a list item by using CacheRequest.Push.
/// </summary>
/// <param name="autoElement">Element from which to retrieve a child element.</param>
/// <remarks>
/// This code demonstrates various aspects of caching. It is not intended to be 
/// an example of a useful method.
/// </remarks>
private void CachePropertiesByPush(AutomationElement elementList)
{
    // Set up the request.
    CacheRequest cacheRequest = new CacheRequest();

    // Do not get a full reference to the cached objects, only to their cached properties and patterns.
    cacheRequest.AutomationElementMode = AutomationElementMode.None;

    // Cache all elements, regardless of whether they are control or content elements.
    cacheRequest.TreeFilter = Automation.RawViewCondition;

    // Property and pattern to cache.
    cacheRequest.Add(AutomationElement.NameProperty);
    cacheRequest.Add(SelectionItemPattern.Pattern);

    // Activate the request.
    cacheRequest.Push();

    // Obtain an element and cache the requested items.
    Condition cond = new PropertyCondition(AutomationElement.IsSelectionItemPatternAvailableProperty, true);
    AutomationElement elementListItem = elementList.FindFirst(TreeScope.Children, cond);

    // At this point, you could call another method that creates a CacheRequest and calls Push/Pop.
    // While that method was retrieving automation elements, the CacheRequest set in this method 
    // would not be active. 

    // Deactivate the request.
    cacheRequest.Pop();

    // Retrieve the cached property and pattern.
    String itemName = elementListItem.Cached.Name;
    SelectionItemPattern pattern = elementListItem.GetCachedPattern(SelectionItemPattern.Pattern) as SelectionItemPattern;

    // The following is an alternative way of retrieving the Name property.
    itemName = elementListItem.GetCachedPropertyValue(AutomationElement.NameProperty) as String;

    // This is yet another way, which returns AutomationElement.NotSupported if the element does
    // not supply a value. If the second parameter is false, a default name is returned.
    object objName = elementListItem.GetCachedPropertyValue(AutomationElement.NameProperty, true);
    if (objName == AutomationElement.NotSupported)
    {
        itemName = "Unknown";
    }
    else
    {
        itemName = objName as String;
    }

    // The following call raises an exception, because only the cached properties are available, 
    //  as specified by cacheRequest.AutomationElementMode. If AutomationElementMode had its
    //  default value (Full), this call would be valid.
    /*** bool enabled = elementListItem.Current.IsEnabled; ***/
}
''' <summary>
''' Caches and retrieves properties for a list item by using CacheRequest.Push.
''' </summary>
''' <param name="elementList">Element from which to retrieve a child element.</param>
''' <remarks>
''' This code demonstrates various aspects of caching. It is not intended to be 
''' an example of a useful method.
''' </remarks>
Private Sub CachePropertiesByPush(ByVal elementList As AutomationElement)
    ' Set up the request.
    Dim cacheRequest As New CacheRequest()

    ' Do not get a full reference to the cached objects, only to their cached properties and patterns.
    cacheRequest.AutomationElementMode = AutomationElementMode.None

    ' Cache all elements, regardless of whether they are control or content elements.
    cacheRequest.TreeFilter = Automation.RawViewCondition

    ' Property and pattern to cache.
    cacheRequest.Add(AutomationElement.NameProperty)
    cacheRequest.Add(SelectionItemPattern.Pattern)

    ' Activate the request.
    cacheRequest.Push()

    ' Obtain an element and cache the requested items.
    Dim myCondition As New PropertyCondition(AutomationElement.IsSelectionItemPatternAvailableProperty, _
        True)
    Dim elementListItem As AutomationElement = elementList.FindFirst(TreeScope.Children, myCondition)

    ' At this point, you could call another method that creates a CacheRequest and calls Push/Pop.
    ' While that method was retrieving automation elements, the CacheRequest set in this method 
    ' would not be active. 
    ' Deactivate the request.
    cacheRequest.Pop()

    ' Retrieve the cached property and pattern.
    Dim itemName As String = elementListItem.Cached.Name
    Dim pattern As SelectionItemPattern = _
        DirectCast(elementListItem.GetCachedPattern(SelectionItemPattern.Pattern), SelectionItemPattern)

    ' The following is an alternative way of retrieving the Name property.
    itemName = CStr(elementListItem.GetCachedPropertyValue(AutomationElement.NameProperty))

    ' This is yet another way, which returns AutomationElement.NotSupported if the element does
    ' not supply a value. If the second parameter is false, a default name is returned.
    Dim objName As Object = elementListItem.GetCachedPropertyValue(AutomationElement.NameProperty, True)
    If objName Is AutomationElement.NotSupported Then
        itemName = "Unknown"
    Else
        itemName = CStr(objName)
    End If
    ' The following call raises an exception, because only the cached properties are available, 
    '  as specified by cacheRequest.AutomationElementMode. If AutomationElementMode had its
    '  default value (Full), this call would be valid.
    '** bool enabled = elementListItem.Current.IsEnabled; **

End Sub

Hinweise

Full der Standardwert ist, und gibt an, dass zurückgegebene Elemente einen vollständigen Verweis auf die zugrunde liegende Benutzeroberfläche enthalten.Full is the default value, and specifies that returned elements contain a full reference to the underlying UI. None Gibt an, dass die zurückgegebenen Elemente keinen Verweis auf die zugrunde liegende Benutzeroberfläche aufweisen und nur zwischengespeicherte Informationen enthalten.None specifies that the returned elements have no reference to the underlying UI, and contain only cached information.

Bestimmte Vorgänge für-Elemente, einschließlich GetCurrentPropertyValue , GetCurrentPattern und SetFocus , erfordern einen vollständigen Verweis. der Versuch, diese für ein Element auszuführen, das keine-Elemente enthält, führt zu einer InvalidOperationException .Certain operations on elements, including GetCurrentPropertyValue, GetCurrentPattern, and SetFocus, require a full reference; attempting to perform these on an element that has none results in an InvalidOperationException.

Die Verwendung von None kann effizienter sein, wenn nur Eigenschaften benötigt werden, da dadurch der Aufwand für das Einrichten vollständiger Verweise vermieden wird.Using None can be more efficient when only properties are needed, as it avoids the overhead involved in setting up full references.

Gilt für: