c# - Windows UI自动化

我正在测试下面的示例代码，无论何时尝试运行它，都会出现如下所示的错误。但是，calc.exe进程已成功执行，因此句柄如何可能为空或零？我希望你明白我想表达的意思。谢谢！代码示例来自http://www.mathpirate.net/log/tag/system-windows-automation/
类型的未处理异常
“System.ArgumentException”发生在
uiautomationclient.dll
附加信息：hwnd不能是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);
}

最佳答案

您误解了WaitForInputIdle（这对该函数当前的功能来说是一个可怕的坏名字）。在创建主窗口之前，您需要主窗口的地址。因此，您最终会将一个无效的窗口句柄传递给其他函数。
编辑：我强烈建议您使用ui自动化库，比如white，如果您打算认真使用它的话。