AutomationElement.FindFirst Method (TreeScope, Condition)
Returns the first child or descendant element that matches the specified condition.
Assembly: UIAutomationClient (in UIAutomationClient.dll)
A bitwise combination of values that specifies the scope of the search.
The object containing the criteria to match.
Return ValueType: System.Windows.Automation.AutomationElement
The first element that satisfies the condition, or null if no match is found.
The scope of the search is relative to the element on which the method is called.
When searching for a top-level window on the desktop, be sure to specify Children in scope, not Descendants. A search through the entire subtree of the desktop could iterate through thousands of items and lead to a stack overflow.
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.
Available since 3.0