AutomationElement.FindFirst(TreeScope, Condition) 方法

定義

傳回符合指定條件的第一個子項目或子系元素。Returns the first child or descendant element that matches the specified condition.

public:
 System::Windows::Automation::AutomationElement ^ FindFirst(System::Windows::Automation::TreeScope scope, System::Windows::Automation::Condition ^ condition);
public System.Windows.Automation.AutomationElement FindFirst (System.Windows.Automation.TreeScope scope, System.Windows.Automation.Condition condition);
member this.FindFirst : System.Windows.Automation.TreeScope * System.Windows.Automation.Condition -> System.Windows.Automation.AutomationElement
Public Function FindFirst (scope As TreeScope, condition As Condition) As AutomationElement

參數

scope
TreeScope

指定搜尋範圍之值的位元組合。A bitwise combination of values that specifies the scope of the search.

condition
Condition

包含符合準則的物件。The object containing the criteria to match.

傳回

AutomationElement

符合條件的第一個元素,沒有符合的元素時則為 nullThe first element that satisfies the condition, or null if no match is found.

範例

下列範例示範如何從識別碼尋找子視窗。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="parentElement">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 AutomationElement FindChildElement(String controlName, AutomationElement rootElement)
{
    if ((controlName == "") || (rootElement == null))
    {
        throw new ArgumentException("Argument cannot be null or empty.");
    }
    // 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.
    Condition propCondition = new PropertyCondition(
        AutomationElement.AutomationIdProperty, controlName, PropertyConditionFlags.IgnoreCase);

    // Find the element.
    return rootElement.FindFirst(TreeScope.Element | TreeScope.Children, propCondition);
}
''' <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

備註

搜尋範圍相對於呼叫方法的元素。The scope of the search is relative to the element on which the method is called.

搜尋桌面上的最上層視窗時,請務必指定 Children in scope 、not DescendantsWhen searching for a top-level window on the desktop, be sure to specify Children in scope, not Descendants. 搜尋整個桌面的整個子樹可逐一查看數以千計的專案,並導致堆疊溢位。A search through the entire subtree of the desktop could iterate through thousands of items and lead to a stack overflow.

如果您的用戶端應用程式可能會嘗試在其本身的使用者介面中尋找元素,您必須在個別的執行緒上進行所有的消費者介面自動化呼叫。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.

適用於

另請參閱