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Find a UI Automation Element Based on a Property Condition

This topic contains example code that shows how to locate an element within the UI Automation tree based on a specific property or properties.

In the following example, a set of property conditions are specified that identify a certain element (or elements) of interest in the AutomationElement tree. A search for all matching elements is then performed with the FindAll method that incorporates a series of AndCondition boolean operations to limit the number of matching elements.

NoteNote:

When searching from the RootElement, you should try to obtain only direct children. A search for descendants might iterate through hundreds or even thousands of elements, possibly resulting in a stack overflow. If you are attempting to obtain a specific element at a lower level, you should start your search from the application window or from a container at a lower level.

///-------------------------------------------------------------------- 
/// <summary> 
/// Walks the UI Automation tree of the target and reports the control  
/// type of each element it finds in the control view to the client. 
/// </summary> 
/// <param name="targetTreeViewElement">
/// The root of the search on this iteration. 
/// </param> 
/// <param name="elementIndex">
/// The TreeView index for this iteration. 
/// </param> 
/// <remarks> 
/// This is a recursive function that maps out the structure of the  
/// subtree of the target beginning at the AutomationElement passed in  
/// as the 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 FindTreeViewDescendants(
    AutomationElement targetTreeViewElement, int treeviewIndex)
{
    if (targetTreeViewElement == null)
        return;

    AutomationElement elementNode =
        TreeWalker.ControlViewWalker.GetFirstChild(targetTreeViewElement);

    while (elementNode != null)
    {
        Label elementInfo = new Label();
        elementInfo.Margin = new Thickness(0);
        clientTreeViews[treeviewIndex].Children.Add(elementInfo);

        // Compile information about the control.
        elementInfoCompile = new StringBuilder();
        string controlName =
            (elementNode.Current.Name == "") ?
            "Unnamed control" : elementNode.Current.Name;
        string autoIdName =
            (elementNode.Current.AutomationId == "") ?
            "No AutomationID" : elementNode.Current.AutomationId;

        elementInfoCompile.Append(controlName)
            .Append(" (")
            .Append(elementNode.Current.ControlType.LocalizedControlType)
            .Append(" - ")
            .Append(autoIdName)
            .Append(")");

        // Test for the control patterns of interest for this sample. 
        object objPattern;
        ExpandCollapsePattern expcolPattern;
        if (true == elementNode.TryGetCurrentPattern(ExpandCollapsePattern.Pattern, out objPattern))
        {
            expcolPattern = objPattern as ExpandCollapsePattern;
            if (expcolPattern.Current.ExpandCollapseState != ExpandCollapseState.LeafNode)
            {
                Button expcolButton = new Button();
                expcolButton.Margin = new Thickness(0, 0, 0, 5);
                expcolButton.Height = 20;
                expcolButton.Width = 100;
                expcolButton.Content = "ExpandCollapse";
                expcolButton.Tag = expcolPattern;
                expcolButton.Click +=
                    new RoutedEventHandler(ExpandCollapse_Click);
                clientTreeViews[treeviewIndex].Children.Add(expcolButton);
            }
        }
        TogglePattern togPattern;
        if (true == elementNode.TryGetCurrentPattern(TogglePattern.Pattern, out objPattern))
        {
            togPattern = objPattern as TogglePattern;
            Button togButton = new Button();
            togButton.Margin = new Thickness(0, 0, 0, 5);
            togButton.Height = 20;
            togButton.Width = 100;
            togButton.Content = "Toggle";
            togButton.Tag = togPattern;
            togButton.Click += new RoutedEventHandler(Toggle_Click);
            clientTreeViews[treeviewIndex].Children.Add(togButton);
        }
        InvokePattern invPattern;
        if (true == elementNode.TryGetCurrentPattern(InvokePattern.Pattern, out objPattern))
        {
            invPattern = objPattern as InvokePattern;
            Button invButton = new Button();
            invButton.Margin = new Thickness(0);
            invButton.Height = 20;
            invButton.Width = 100;
            invButton.Content = "Invoke";
            invButton.Tag = invPattern;
            invButton.Click += new RoutedEventHandler(Invoke_Click);
            clientTreeViews[treeviewIndex].Children.Add(invButton);
        }
        // Display compiled information about the control.
        elementInfo.Content = elementInfoCompile;
        Separator sep = new Separator();
        clientTreeViews[treeviewIndex].Children.Add(sep);

        // Iterate to next element. 
        // elementNode - Current element. 
        // treeviewIndex - Index of parent TreeView.
        FindTreeViewDescendants(elementNode, treeviewIndex);
        elementNode = 
            TreeWalker.ControlViewWalker.GetNextSibling(elementNode);
    }
}
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