AutomationElement.FindFirst Method (TreeScope, Condition)


Returns the first child or descendant element that matches the specified condition.

Namespace:   System.Windows.Automation
Assembly:  UIAutomationClient (in UIAutomationClient.dll)

Public Function FindFirst (
	scope As TreeScope,
	condition As Condition
) As AutomationElement


Type: System.Windows.Automation.TreeScope

A bitwise combination of values that specifies the scope of the search.

Type: System.Windows.Automation.Condition

The object containing the criteria to match.

Return Value

Type: 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.

The following example shows how to find a child window from its identifier.

''' <summary>
''' Find a UI Automation child element by ID.
''' </summary>
''' <param name="controlName">Name of the control, such as "button1"</param>
''' <param name="rootElement">Parent element, such as an application window, or the 
''' AutomationElement.RootElement when searching for the application window.</param>
''' <returns>The UI Automation element.</returns>
Private Function FindChildElement(ByVal controlName As String, ByVal rootElement As AutomationElement) _
    As AutomationElement
    If controlName = "" OrElse rootElement Is Nothing Then
        Throw New ArgumentException("Argument cannot be null or empty.")
    End If
    ' Set a property condition that will be used to find the main form of the
    ' target application. In the case of a WinForms control, the name of the control
    ' is also the AutomationId of the element representing the control.
    Dim propCondition As New PropertyCondition(AutomationElement.AutomationIdProperty, _
        controlName, PropertyConditionFlags.IgnoreCase)

    ' Find the element.
    Return rootElement.FindFirst(TreeScope.Element Or TreeScope.Children, propCondition)

End Function 'FindChildElement

.NET Framework
Available since 3.0
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