TreeWalker を使用した UI オートメーション要素間の移動

メモメモ

このドキュメントは、System.Windows.Automation 名前空間で定義されているマネージ UI Automation クラスを使用する .NET Framework 開発者を対象としています。UI Automationに関する最新情報については、「Windows Automation API: UI Automation (Windows オートメーション API: UI オートメーション)」を参照してください。

このトピックのコード例では、TreeWalker クラスを使用して Microsoft UI Automation要素間を移動する方法を示します。

使用例

GetParent を使用して、ルート要素であるデスクトップを見つけるまで Microsoft UI Automation ツリーを上方向へ移動する例を次に示します。 そのすぐ下の要素は指定した要素の親ウィンドウです。

    ''' <summary>
    ''' Retrieves the top-level window that contains the specified UI Automation element.
    ''' </summary>
    ''' <param name="element">The contained element.</param>
    ''' <returns>The containing top-level window element.</returns>
    Private Function GetTopLevelWindow(ByVal element As AutomationElement) As AutomationElement 
        Dim walker As TreeWalker = TreeWalker.ControlViewWalker
        Dim elementParent As AutomationElement
        Dim node As AutomationElement = element
        If node = elementRoot Then
            Return node
        End If
        Do
            elementParent = walker.GetParent(node)
            If elementParent = AutomationElement.RootElement Then
                Exit Do
            End If
            node = elementParent
        Loop While True
        Return node

    End Function 'GetTopLevelWindow
End Class 'Reader 
/// <summary>
/// Retrieves the top-level window that contains the specified UI Automation element.
/// </summary>
/// <param name="element">The contained element.</param>
/// <returns>The containing top-level window element.</returns>
private AutomationElement GetTopLevelWindow(AutomationElement element)
{
    TreeWalker walker = TreeWalker.ControlViewWalker;
    AutomationElement elementParent;
    AutomationElement node = element;
    if (node == elementRoot) return node;
    do
    {
        elementParent = walker.GetParent(node);
        if (elementParent == AutomationElement.RootElement) break;
        node = elementParent;
    }
    while (true);
    return node;
}

次の例では、GetFirstChildGetNextSibling を使用して、コントロール ビュー内にある有効な Microsoft UI Automation要素のサブツリー全体を表示する TreeView を作成します。

    ''' <summary>
    ''' Walks the UI Automation tree and adds the control type of each enabled control 
    ''' element it finds to a TreeView.
    ''' </summary>
    ''' <param name="rootElement">The root of the search on this iteration.</param>
    ''' <param name="treeNode">The node in the TreeView for this iteration.</param>
    ''' <remarks>
    ''' This is a recursive function that maps out the structure of the subtree beginning at the
    ''' UI Automation element passed in as rootElement on the first call. This could be, for example,
    ''' an application window.
    ''' CAUTION: Do not pass in AutomationElement.RootElement. Attempting to map out the entire subtree of
    ''' the desktop could take a very long time and even lead to a stack overflow.
    ''' </remarks>
    Private Sub WalkEnabledElements(ByVal rootElement As AutomationElement, ByVal treeNode As TreeNode)
        Dim condition1 As New PropertyCondition(AutomationElement.IsControlElementProperty, True)
        Dim condition2 As New PropertyCondition(AutomationElement.IsEnabledProperty, True)
        Dim walker As New TreeWalker(New AndCondition(condition1, condition2))
        Dim elementNode As AutomationElement = walker.GetFirstChild(rootElement)
        While (elementNode IsNot Nothing)
            Dim childTreeNode As TreeNode = treeNode.Nodes.Add(elementNode.Current.ControlType.LocalizedControlType)
            WalkEnabledElements(elementNode, childTreeNode)
            elementNode = walker.GetNextSibling(elementNode)
        End While

    End Sub 'WalkEnabledElements

/// <summary>
/// Walks the UI Automation tree and adds the control type of each enabled control 
/// element it finds to a TreeView.
/// </summary>
/// <param name="rootElement">The root of the search on this iteration.</param>
/// <param name="treeNode">The node in the TreeView for this iteration.</param>
/// <remarks>
/// This is a recursive function that maps out the structure of the subtree beginning at the
/// UI Automation element passed in as rootElement on the first call. This could be, for example,
/// an application window.
/// CAUTION: Do not pass in AutomationElement.RootElement. Attempting to map out the entire subtree of
/// the desktop could take a very long time and even lead to a stack overflow.
/// </remarks>
private void WalkEnabledElements(AutomationElement rootElement, TreeNode treeNode)
{
    Condition condition1 = new PropertyCondition(AutomationElement.IsControlElementProperty, true);
    Condition condition2 = new PropertyCondition(AutomationElement.IsEnabledProperty, true);
    TreeWalker walker = new TreeWalker(new AndCondition(condition1, condition2));
    AutomationElement elementNode = walker.GetFirstChild(rootElement);
    while (elementNode != null)
    {
        TreeNode childTreeNode = treeNode.Nodes.Add(elementNode.Current.ControlType.LocalizedControlType);
        WalkEnabledElements(elementNode, childTreeNode);
        elementNode = walker.GetNextSibling(elementNode);
    }
}

参照

概念

UI オートメーション要素の取得