Navegar entre elementos de UI Automation con TreeWalker
Nota
Esta documentación está dirigida a los desarrolladores de .NET Framework que quieran usar las clases de automatización de la interfaz de usuario administradas definidas en el espacio de nombres System.Windows.Automation. Para ver la información más reciente acerca de la automatización de la interfaz de usuario, consulte Windows Automation API: automatización de la interfaz de usuario.
Este tema contiene código de ejemplo que muestra cómo navegar entre los elementos de Microsoft Automatización de la interfaz de usuario mediante la clase TreeWalker.
Ejemplo 1
En el ejemplo siguiente se usa GetParent para recorrer el árbol de Microsoft Automatización de la interfaz de usuario hasta que encuentre el elemento raíz o el escritorio. Elemento justo debajo que es la ventana primaria del 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
Ejemplo 2
En el ejemplo siguiente se usa GetFirstChild y GetNextSibling para crear un objetoTreeView que muestra un subárbol completo de Microsoft Automatización de la interfaz de usuario elementos que están en la vista de control y que están 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