AutomationElement.GetUpdatedCache(CacheRequest) 方法

定义

命名空间:

System.Windows.Automation

程序集:

UIAutomationClient.dll

检索一个具有更新缓存的新 AutomationElement。

public:
 System::Windows::Automation::AutomationElement ^ GetUpdatedCache(System::Windows::Automation::CacheRequest ^ request);

public System.Windows.Automation.AutomationElement GetUpdatedCache (System.Windows.Automation.CacheRequest request);

member this.GetUpdatedCache : System.Windows.Automation.CacheRequest -> System.Windows.Automation.AutomationElement

Public Function GetUpdatedCache (request As CacheRequest) As AutomationElement

参数

request

CacheRequest

将包含在更新的缓存中的模式和属性。

返回

AutomationElement

一个具有更新缓存的新的 AutomationElement。

示例

以下示例演示了在组合框中的选择发生更改时如何更新缓存。

CacheRequest comboCacheRequest;
AutomationEventHandler selectHandler;
AutomationElement elementCombo;
AutomationElement selectedItem;

/// <summary>
/// Retrieves a combo box automation element, caches a pattern and a property,
/// and registers the event handler.
/// </summary>
/// <param name="elementAppWindow">The element for the parent window.</param>
private void SetupComboElement(AutomationElement elementAppWindow)
{
    // Set up the CacheRequest.
    comboCacheRequest = new CacheRequest();
    comboCacheRequest.Add(SelectionPattern.Pattern);
    comboCacheRequest.Add(SelectionPattern.SelectionProperty);
    comboCacheRequest.Add(AutomationElement.NameProperty);
    comboCacheRequest.TreeScope = TreeScope.Element | TreeScope.Descendants;

    // Activate the CacheRequest and get the element.
    using (comboCacheRequest.Activate())
    {
        // Load the combo box element and cache the specified properties and patterns.
        Condition propCondition = new PropertyCondition(
            AutomationElement.AutomationIdProperty, "comboBox1", PropertyConditionFlags.IgnoreCase);
        elementCombo = elementAppWindow.FindFirst(TreeScope.Descendants, propCondition);
    }

    // Get the list from the combo box.
    Condition propCondition1 = new PropertyCondition(AutomationElement.ControlTypeProperty, ControlType.List);
    AutomationElement listElement = elementCombo.FindFirst(TreeScope.Children, propCondition1);

    // Register for ElementSelectedEvent on list items.
    if (listElement != null)
    {
        Automation.AddAutomationEventHandler(SelectionItemPattern.ElementSelectedEvent, listElement,
            TreeScope.Children, selectHandler = new AutomationEventHandler(OnListItemSelect));
    }
}

/// <summary>
/// Handle ElementSelectedEvent on items in the combo box.
/// </summary>
/// <param name="src">Object that raised the event.</param>
/// <param name="e">Event arguments.</param>
private void OnListItemSelect(object src, AutomationEventArgs e)
{
    // Update the cache.
    AutomationElement updatedElement = elementCombo.GetUpdatedCache(comboCacheRequest);

    // Retrieve the pattern and the selected item from the cache. This code is here only to 
    // demonstrate that the current selection can now be retrieved from the cache. In an application,
    // this would be done only when the information was needed.
    SelectionPattern pattern = updatedElement.GetCachedPattern(SelectionPattern.Pattern) as SelectionPattern;
    AutomationElement[] selectedItems = pattern.Cached.GetSelection();
    selectedItem = selectedItems[0];
}

Private comboCacheRequest As CacheRequest
Private selectHandler As AutomationEventHandler
Private elementCombo As AutomationElement
Private selectedItem As AutomationElement


''' <summary>
''' Retrieves a combo box automation element, caches a pattern and a property,
''' and registers the event handler.
''' </summary>
''' <param name="elementAppWindow">The element for the parent window.</param>
Private Sub SetupComboElement(ByVal elementAppWindow As AutomationElement)
    ' Set up the CacheRequest.
    comboCacheRequest = New CacheRequest()
    comboCacheRequest.Add(SelectionPattern.Pattern)
    comboCacheRequest.Add(SelectionPattern.SelectionProperty)
    comboCacheRequest.Add(AutomationElement.NameProperty)
    comboCacheRequest.TreeScope = TreeScope.Element Or TreeScope.Descendants

    ' Activate the CacheRequest and get the element.
    Using comboCacheRequest.Activate()
        ' Load the combo box element and cache the specified properties and patterns.
        Dim propCondition As New PropertyCondition(AutomationElement.AutomationIdProperty, "comboBox1", PropertyConditionFlags.IgnoreCase)
        elementCombo = elementAppWindow.FindFirst(TreeScope.Descendants, propCondition)

        ' Get the list from the combo box.
        Dim propCondition1 As New PropertyCondition(AutomationElement.ControlTypeProperty, ControlType.List)
        Dim listElement As AutomationElement = elementCombo.FindFirst(TreeScope.Children, propCondition1)

        ' Register for ElementSelectedEvent on list items.
        selectHandler = New AutomationEventHandler(AddressOf OnListItemSelect)
        If (listElement IsNot Nothing) Then
            Automation.AddAutomationEventHandler(SelectionItemPattern.ElementSelectedEvent, listElement, _
            TreeScope.Children, selectHandler)
        End If
    End Using

End Sub


''' <summary>
''' Handle ElementSelectedEvent on items in the combo box.
''' </summary>
''' <param name="src">Object that raised the event.</param>
''' <param name="e">Event arguments.</param>
Private Sub OnListItemSelect(ByVal src As Object, ByVal e As AutomationEventArgs)
    ' Update the cache.
    Dim updatedElement As AutomationElement = elementCombo.GetUpdatedCache(comboCacheRequest)

    ' Retrieve the pattern and the selected item from the cache. This code is here only to 
    ' demonstrate that the current selection can now be retrieved from the cache. In an application,
    ' this would be done only when the information was needed.
    Dim pattern As SelectionPattern = _
        DirectCast(updatedElement.GetCachedPattern(SelectionPattern.Pattern), SelectionPattern)
    Dim selectedItems As AutomationElement() = pattern.Cached.GetSelection()
    selectedItem = selectedItems(0)

End Sub

注解

原始 AutomationElement 值保持不变。 GetUpdatedCache返回一个新的 AutomationElement，它引用同一用户界面 (UI) ，并且具有相同。RuntimeIdProperty

另请参阅

• 在 UI 自动化客户端中缓存