使用 AutomationID 属性
备注
本文档适用于想要使用 System.Windows.Automation 命名空间中定义的托管 UI 自动化类的 .NET Framework 开发人员。 有关 UI 自动化的最新信息，请参阅 Windows 自动化 API：UI 自动化。
本主题包含一些方案和代码示例，这些方案和代码示例演示如何以及在何时能够使用 AutomationIdProperty 在 UI 自动化树中找到元素。
AutomationIdProperty 唯一地将 UI 自动化元素从其同级中标识出来。 有关与控件标识相关的属性标识符的详细信息，请参阅 UI Automation Properties Overview。
备注
AutomationIdProperty 不保证标识在整个树中的唯一性；它通常需要容器和范围信息才有用。 例如，一个应用程序可能包含具有多个顶级菜单项的菜单控件，而这些顶级菜单项又具有多个子菜单项。 这些二级菜单项通过常规架构（如“Item1”、“Item2”，依此类推）进行标识，允许对顶级菜单项中的子菜单项使用重复的标识符。
方案
已确定有三个主要的 UI 自动化客户端应用程序方案需要使用 AutomationIdProperty 才能在搜索元素时获得准确一致的结果。
备注
控件视图中（除顶级应用程序窗口外）的所有 UI 自动化元素、派生自没有 ID 或 x:Uid 的 Windows Presentation Foundation (WPF) 控件的 UI 自动化元素以及派生自没有控件 ID 的 Win32 控件的 UI 自动化元素都支持 AutomationIdProperty。
使用唯一且可发现的 AutomationID 在 UI 自动化树中查找特定元素
- 使用 UI Spy 等工具来报告关注的 UI 元素的 AutomationIdProperty。 然后，可以将此值复制并粘贴到客户端应用程序（如测试脚本）中，以便随后进行自动化测试。 此方法减少并简化了在运行时标识和查找元素所需的代码。
注意
通常，你应当尝试只获取 RootElement的直接子项。 对后代的搜索可能循环访问数百个甚至数千个元素，这可能导致堆栈溢出。 如果尝试在较低级别上获取特定元素，应该从应用程序窗口或者从较低级别的容器中开始搜索。
///--------------------------------------------------------------------
/// <summary>
/// Finds all elements in the UI Automation tree that have a specified
/// AutomationID.
/// </summary>
/// <param name="targetApp">
/// The root element from which to start searching.
/// </param>
/// <param name="automationID">
/// The AutomationID value of interest.
/// </param>
/// <returns>
/// The collection of UI Automation elements that have the specified
/// AutomationID value.
/// </returns>
///--------------------------------------------------------------------
private AutomationElementCollection FindElementFromAutomationID(AutomationElement targetApp,
string automationID)
{
return targetApp.FindAll(
TreeScope.Descendants,
new PropertyCondition(AutomationElement.AutomationIdProperty, automationID));
}
'''--------------------------------------------------------------------
''' <summary>
''' Finds all elements in the UI Automation tree that have a specified
''' AutomationID.
''' </summary>
''' <param name="targetApp">
''' The root element from which to start searching.
''' </param>
''' <param name="automationID">
''' The AutomationID value of interest.
''' </param>
''' <returns>
''' The collection of automation elements that have the specified
''' AutomationID value.
''' </returns>
'''--------------------------------------------------------------------
Private Function FindElementFromAutomationID( _
ByVal targetApp As AutomationElement, _
ByVal automationID As String) As AutomationElementCollection
Return targetApp.FindAll( _
TreeScope.Descendants, _
New PropertyCondition( _
AutomationElement.AutomationIdProperty, automationID))
End Function 'FindElementFromAutomationID
使用持久的路径返回到之前标识的 AutomationElement
- 客户端应用程序（从简单的测试脚本到强大的录制和播放实用程序）可能需要访问当前未实例化并因此不存在于 UI 自动化树中的元素（如打开文件对话框或菜单项）。 只能使用 UI 自动化属性（例如 AutomationID）控件模式和事件侦听器，通过重现（或“播放”）特定的一系列 UI 操作来实例化这些元素。
///--------------------------------------------------------------------
/// <summary>
/// Creates a UI Automation thread.
/// </summary>
/// <param name="sender">Object that raised the event.</param>
/// <param name="e">Event arguments.</param>
/// <remarks>
/// UI Automation must be called on a separate thread if the client
/// application itself could become a target for event handling.
/// For example, focus tracking is a desktop event that could involve
/// the client application.
/// </remarks>
///--------------------------------------------------------------------
private void CreateUIAThread(object sender, EventArgs e)
{
// Start another thread to do the UI Automation work.
ThreadStart threadDelegate = new ThreadStart(CreateUIAWorker);
Thread workerThread = new Thread(threadDelegate);
workerThread.Start();
}
///--------------------------------------------------------------------
/// <summary>
/// Delegated method for ThreadStart. Creates a UI Automation worker
/// class that does all UI Automation related work.
/// </summary>
///--------------------------------------------------------------------
public void CreateUIAWorker()
{
uiautoWorker = new FindByAutomationID(targetApp);
}
private FindByAutomationID uiautoWorker;
'''--------------------------------------------------------------------
''' <summary>
''' Creates a UI Automation thread.
''' </summary>
''' <param name="sender">Object that raised the event.</param>
''' <param name="e">Event arguments.</param>
''' <remarks>
''' UI Automation must be called on a separate thread if the client
''' application itself could become a target for event handling.
''' For example, focus tracking is a desktop event that could involve
''' the client application.
''' </remarks>
'''--------------------------------------------------------------------
Private Sub CreateUIAThread(ByVal sender As Object, ByVal e As EventArgs)
' Start another thread to do the UI Automation work.
Dim threadDelegate As New ThreadStart(AddressOf CreateUIAWorker)
Dim workerThread As New Thread(threadDelegate)
workerThread.Start()
End Sub
'''--------------------------------------------------------------------
''' <summary>
''' Delegated method for ThreadStart. Creates a UI Automation worker
''' class that does all UI Automation related work.
''' </summary>
'''--------------------------------------------------------------------
Public Sub CreateUIAWorker()
uiautoWorker = New UIAWorker(targetApp)
End Sub
Private uiautoWorker As UIAWorker
///--------------------------------------------------------------------
/// <summary>
/// Function to playback through a series of recorded events calling
/// a WriteToScript function for each event of interest.
/// </summary>
/// <remarks>
/// A major drawback to using AutomationID for recording user
/// interactions in a volatile UI is the probability of catastrophic
/// change in the UI. For example, the //Processes// dialog where items
/// in the listbox container can change with no input from the user.
/// This mandates that a record and playback application must be
/// reliant on the tester owning the UI being tested. In other words,
/// there has to be a contract between the provider and client that
/// excludes uncontrolled, external applications. The added benefit
/// is the guarantee that each control in the UI should have an
/// AutomationID assigned to it.
///
/// This function relies on a UI Automation worker class to create
/// the System.Collections.Generic.Queue object that stores the
/// information for the recorded user interactions. This
/// allows post-processing of the recorded items prior to actually
/// writing them to a script. If this is not necessary the interaction
/// could be written to the script immediately.
/// </remarks>
///--------------------------------------------------------------------
private void Playback(AutomationElement targetApp)
{
AutomationElement element;
foreach(ElementStore storedItem in uiautoWorker.elementQueue)
{
PropertyCondition propertyCondition =
new PropertyCondition(
AutomationElement.AutomationIdProperty, storedItem.AutomationID);
// Confirm the existence of a control.
// Depending on the controls and complexity of interaction
// this step may not be necessary or may require additional
// functionality. For example, to confirm the existence of a
// child menu item that had been invoked the parent menu item
// would have to be expanded.
element = targetApp.FindFirst(TreeScope.Descendants, propertyCondition);
if(element == null)
{
// Control not available, unable to continue.
// TODO: Handle error condition.
return;
}
WriteToScript(storedItem.AutomationID, storedItem.EventID);
}
}
///--------------------------------------------------------------------
/// <summary>
/// Generates script code and outputs the code to a text control in
/// the client.
/// </summary>
/// <param name="automationID">
/// The AutomationID of the current control.
/// </param>
/// <param name="eventID">
/// The event recorded on that control.
/// </param>
///--------------------------------------------------------------------
private void WriteToScript(string automationID, string eventID)
{
// Script code would be generated and written to an output file
// as plain text at this point, but for the
// purposes of this example we just write to the console.
Console.WriteLine(automationID + " - " + eventID);
}
'''--------------------------------------------------------------------
''' <summary>
''' Function to playback through a series of recorded events calling
''' a WriteToScript function for each event of interest.
''' </summary>
''' <remarks>
''' A major drawback to using AutomationID for recording user
''' interactions in a volatile UI is the probability of catastrophic
''' change in the UI. For example, the 'Processes' dialog where items
''' in the listbox container can change with no input from the user.
''' This mandates that a record and playback application must be
''' reliant on the tester owning the UI being tested. In other words,
''' there has to be a contract between the provider and client that
''' excludes uncontrolled, external applications. The added benefit
''' is the guarantee that each control in the UI should have an
''' AutomationID assigned to it.
'''
''' This function relies on a UI Automation worker class to create
''' the System.Collections.Generic.Queue object that stores the
''' information for the recorded user interactions. This
''' allows post-processing of the recorded items prior to actually
''' writing them to a script. If this is not necessary the interaction
''' could be written to the script immediately.
''' </remarks>
'''--------------------------------------------------------------------
Private Sub Playback(ByVal targetApp As AutomationElement)
Dim element As AutomationElement
Dim storedItem As ElementStore
For Each storedItem In uiautoWorker.elementQueue
Dim propertyCondition As New PropertyCondition( _
AutomationElement.AutomationIdProperty, storedItem.AutomationID)
' Confirm the existence of a control.
' Depending on the controls and complexity of interaction
' this step may not be necessary or may require additional
' functionality. For example, to confirm the existence of a
' child menu item that had been invoked the parent menu item
' would have to be expanded.
element = targetApp.FindFirst( _
TreeScope.Descendants, propertyCondition)
If element Is Nothing Then
' Control not available, unable to continue.
' TODO: Handle error condition.
Return
End If
WriteToScript(storedItem.AutomationID, storedItem.EventID)
Next storedItem
End Sub
'''--------------------------------------------------------------------
''' <summary>
''' Generates script code and outputs the code to a text control in
''' the client.
''' </summary>
''' <param name="automationID">
''' The AutomationID of the current control.
''' </param>
''' <param name="eventID">
''' The event recorded on that control.
''' </param>
'''--------------------------------------------------------------------
Private Sub WriteToScript( _
ByVal automationID As String, ByVal eventID As String)
' Script code would be generated and written to an output file
' as plain text at this point, but for the
' purposes of this example we just write to the console.
Console.WriteLine(automationID + " - " + eventID)
End Sub
使用相对路径返回到之前标识的 AutomationElement
- 在某些情况下，由于只能保证 AutomationID 在同级项之间唯一，因此 UI 自动化树中的多个元素可能具有相同的 AutomationID 属性值。 对于这些情况，可以基于父项（必要情况下使用其祖父项）来唯一地标识元素。 例如，开发人员可能提供一个包含多个菜单项（其中每个菜单项又包含多个子菜单项）的菜单栏，其中的子项是用连续的 AutomationID（如“Item1”、“Item2”，依此类推）标识的。 然后，可以通过其 AutomationID 以及其父项（必要情况下使用其祖父项）的 AutomationID 来唯一地标识每个菜单项。