TreeWalker.ControlViewWalker Field

Reference

Definition

Namespace:: System.Windows.Automation

Assembly:: UIAutomationClient.dll

Important

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Represents a predefined TreeWalker containing a view of elements in the tree that are marked as controls.

public: static initonly System::Windows::Automation::TreeWalker ^ ControlViewWalker;

public static readonly System.Windows.Automation.TreeWalker ControlViewWalker;

 staticval mutable ControlViewWalker : System.Windows.Automation.TreeWalker

Public Shared ReadOnly ControlViewWalker As TreeWalker

Field Value

TreeWalker

Examples

The following example shows ControlViewWalker being used to construct a tree view of elements in a subtree.

/// <summary>
/// Walks the UI Automation tree and adds the control type of each element it finds 
/// in the control view 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 WalkControlElements(AutomationElement rootElement, TreeNode treeNode)
{
    // Conditions for the basic views of the subtree (content, control, and raw) 
    // are available as fields of TreeWalker, and one of these is used in the 
    // following code.
    AutomationElement elementNode = TreeWalker.ControlViewWalker.GetFirstChild(rootElement);

    while (elementNode != null)
    {
        TreeNode childTreeNode = treeNode.Nodes.Add(elementNode.Current.ControlType.LocalizedControlType);
        WalkControlElements(elementNode, childTreeNode);
        elementNode = TreeWalker.ControlViewWalker.GetNextSibling(elementNode);
    }
}

''' <summary>
''' Walks the UI Automation tree and adds the control type of each element it finds 
''' in the control view 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 WalkControlElements(ByVal rootElement As AutomationElement, ByVal treeNode As TreeNode)
    ' Conditions for the basic views of the subtree (content, control, and raw) 
    ' are available as fields of TreeWalker, and one of these is used in the 
    ' following code.
    Dim elementNode As AutomationElement = TreeWalker.ControlViewWalker.GetFirstChild(rootElement)

    While (elementNode IsNot Nothing)
        Dim childTreeNode As TreeNode = treeNode.Nodes.Add(elementNode.Current.ControlType.LocalizedControlType)
        WalkControlElements(elementNode, childTreeNode)
        elementNode = TreeWalker.ControlViewWalker.GetNextSibling(elementNode)
    End While

End Sub

Remarks

If your client application might try to find elements in its own user interface, you must make all UI Automation calls on a separate thread.

Applies to

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