Windows UI 自动化

Question

我正在测试下面的示例代码，不知何故，每当我尝试运行它时，都会出现如下所示的错误。但是，calc.exe 进程已成功执行，那么句柄怎么可能为 null 或为零呢？我希望你能理解我想要表达的意思。谢谢！代码示例来自http://www.mathpirate.net/log/tag/system-windows-automation/

未处理的类型异常 'System.ArgumentException' 发生在 UIAutomationClient.dll 附加信息：hwnd 不能为 IntPtr.Zero 或 null。

//Launches the Windows Calculator and gets the Main Window's Handle.
Process calculatorProcess = Process.Start("calc.exe");
calculatorProcess.WaitForInputIdle();
IntPtr calculatorWindowHandle = calculatorProcess.MainWindowHandle;

//Here I use a window handle to get an AutomationElement for a specific window.
AutomationElement calculatorElement = AutomationElement.FromHandle(calculatorWindowHandle);

if(calculatorElement == null)
{
    throw new Exception("Uh-oh, couldn't find the calculator...");
}

//Walks some of the more interesting properties on the AutomationElement.
Console.WriteLine("--------Element");
Console.WriteLine("AutomationId: {0}", calculatorElement.Current.AutomationId);
Console.WriteLine("Name: {0}", calculatorElement.Current.Name);
Console.WriteLine("ClassName: {0}", calculatorElement.Current.ClassName);
Console.WriteLine("ControlType: {0}", calculatorElement.Current.ControlType.ProgrammaticName);
Console.WriteLine("IsEnabled: {0}", calculatorElement.Current.IsEnabled);
Console.WriteLine("IsOffscreen: {0}", calculatorElement.Current.IsOffscreen);
Console.WriteLine("ProcessId: {0}", calculatorElement.Current.ProcessId);

//Commented out because it requires another library reference. However, it's useful to see that this exists.
//Console.WriteLine("BoundingRectangle: {0}", calculatorElement.Current.BoundingRectangle);

Console.WriteLine("Supported Patterns:");
foreach (AutomationPattern supportedPattern in calculatorElement.GetSupportedPatterns())
{
    Console.WriteLine("\t{0}", supportedPattern.ProgrammaticName);
}

Answer 1

您误解了WaitForInputIdle（对于该功能当前的功能来说，这是一个非常糟糕的名字）。您甚至在创建主窗口之前就要求提供主窗口的地址。结果，您最终将无效的窗口句柄传递给您的其他函数。

编辑：如果您打算认真使用它，我强烈建议您使用 UI 自动化库，例如 white。