Navegue entre os elementos de automação da interface do usuário com o TreeWalker
Nota
Esta documentação destina-se a desenvolvedores do .NET Framework que desejam usar as classes de automação da interface do usuário gerenciadas definidas no System.Windows.Automation namespace. Para obter as informações mais recentes sobre a automação da interface do usuário, consulte API de automação do Windows: automação da interface do usuário.
Este tópico contém código de exemplo que mostra como navegar entre os elementos de automação da interface do usuário da Microsoft usando a TreeWalker classe.
Exemplo 1
O exemplo a seguir usa GetParent para percorrer a árvore de automação da interface do usuário da Microsoft até encontrar o elemento raiz ou área de trabalho. O elemento logo abaixo 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 um TreeView que mostra uma subárvore inteira de elementos de automação da interface do usuário da Microsoft que estão no modo de exibição de controle e que estão habilitados.
/// <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