Navegar em elementos de automação de interface do usuário com TreeWalker

Este tópico contém código de exemplo que mostra como navegar entre elementos de Automação da Interface do Usuário Microsoft usando a classe TreeWalker.

Exemplo 1

O exemplo a seguir usa GetParent para percorrer a árvore de Automação da Interface do Usuário Microsoft até encontrar o elemento raiz ou a área de trabalho. O elemento visto logo abaixo, que é a janela pai do elemento especificado.

/// <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;
}

    ''' <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

Exemplo 2

O exemplo a seguir usa GetFirstChild e GetNextSibling para criar uma TreeView que mostra toda uma subárvore de elementos de Automação da Interface do Usuário Microsoft que estão habilitados e no modo de exibição de controle.

/// <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);
    }
}

''' <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

Confira também

• Obtendo elementos da automação interface do usuário