Windows用戶界面自動化

Question

我正在測試下面的示例代碼，並且每當我嘗試運行它時，我都會遇到下面顯示的錯誤。但是，calc.exe進程執行成功，那麼句柄如何可能爲null或零？我希望你明白我想表達的意思。謝謝！該代碼樣品來自http://www.mathpirate.net/log/tag/system-windows-automation/

類型 「System.ArgumentException」的未處理的異常發生在 UIAutomationClient.dll 其他信息：HWND不能IntPtr.Zero或空。

//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

你誤會WaitForInputIdle（這是什麼功能目前做了窘況壞名）。在主窗口創建之前，您正在詢問主窗口的地址。因此，最終會將無效的窗口句柄傳遞給其他函數。

編輯：我會強烈建議使用一個UI自動化庫，如white，如果你要做的嚴肅的工作。