Question

在我的一个程序中，我使用rundll32.exe url.dll,FileProtocolHandler c:\path\to\a.file打开文件。我想处理错误，以防这个文件无法打开，但我无法弄清楚如何找出是否有错误。那是我的代码：

QProcess::startDetached( QString( "rundll32.exe url.dll,FileProtocolHandler " + p_target_path ) );

startDetached()现在总是返回true，因为它在打开包含rundll32.exe的进程时总是成功的。那么我怎么知道我的文件是否可以找到/打开？

我在* .bat文件中尝试了errorlevel-things进行测试。

rundll32.exe url.dll,FileProtocolHandler c:\not_existing.exe >nul || echo Could not open file.

但没有任何回应。我也尝试读取％ERRORLEVEL％，但即使文件不存在，errorlevel也保持为0.

有没有人知道如何处理这个问题？

Answer 1

在我看来，rundll32.exe确实没有返回erorlevel。您可以看一下http://support.microsoft.com/kb/164787，Rundll32接口没有定义的返回错误的方法。

VOID CALLBACK FileProtocolHandler (
  __in  HWND hwnd,
  __in  HINSTANCE ModuleHandle,
  __in  PCTSTR pszCmdLineBuffer,
  __in  INT nCmdShow
);

顺便说一句，您可以直接调用url.dll导出的函数FileProtocolHandler，而无需启动rundll32.exe。作为pszCmdLineBuffer，您可以p_target_path。然而，您将不会收到任何错误信息。

更新：顺便说一下，如果您使用rundll32.exe url.dll,FileProtocolHandler仅打开文件而不是网址，则可以使用ShellExecute或ShellExecuteEx代替动词“打开“或NULL（见http://msdn.microsoft.com/en-us/library/bb776886.aspx）。在最简单的情况下，代码可能如下所示

HINSTANCE hInst = ShellExecute（NULL，TEXT（“open”）， TEXT（“c：\ path \ to \ a.file”），NULL，NULL，0）;

您可以针对错误测试hInst（请参阅http://msdn.microsoft.com/en-us/library/bb762153.aspx中的返回值）

Answer 2

是的，甚至在您撰写评论之前，我就开始正确地阅读文档，并在不到2分钟的时间内得到了解决方案：

void main_window::open_test( QString p_target_path )
{
    p_target_path = p_target_path.remove( "\"" );

    HINSTANCE res = ShellExecute( NULL, TEXT("open"), (LPCWSTR) p_target_path.utf16(), NULL, NULL, SW_SHOWNORMAL );

    QString err_str = "";

    int res_code = (int) res;

    switch( res_code )
    {
    case 0:
        err_str = "Your operating system is out of memory or resources.";
        break;
    case ERROR_FILE_NOT_FOUND:
        err_str = "The specified file was not found.";
        break;
    case ERROR_PATH_NOT_FOUND:
        err_str = "The specified path was not found.";
        break;
    case ERROR_BAD_FORMAT:
        err_str = "The .exe file is invalid (non-Win32 .exe or error in .exe image).";
        break;
    case SE_ERR_ACCESSDENIED:
        err_str = "Your operating system denied access to the specified file.";
        break;
    case SE_ERR_ASSOCINCOMPLETE:
        err_str = "The file name association is incomplete or invalid.";
        break;
    case SE_ERR_DDEBUSY:
        err_str = "The DDE transaction could not be completed because other DDE transactions were being processed.";
        break;
    case SE_ERR_DDEFAIL:
        err_str = "The DDE transaction failed.";
        break;
    case SE_ERR_DDETIMEOUT:
        err_str = "The DDE transaction could not be completed because the request timed out.";
        break;
    case SE_ERR_DLLNOTFOUND:
        err_str = "The specified DLL was not found.";
        break;
    case SE_ERR_NOASSOC:
        err_str = "There is no application associated with the given file name extension.\nThis error will also be returned if you attempt to print a file that is not printable.";
        break;
    case SE_ERR_OOM:
        err_str = "There was not enough memory to complete the operation.";
        break;
    case SE_ERR_SHARE:
        err_str = "A sharing violation occurred.";
        break;
    default:
        return;
    }

    QMessageBox::warning( this, "Error", err_str );
}

有没有办法从FileProtocolHandler或url.dll获取错误级别？

2 个答案: