从 C# 结果 0 输出通过 CMD.exe 调用“查询用户”

Posted 2023-02-19

【中文标题】从 C# 结果 0 输出通过 CMD.exe 调用“查询用户”

【英文标题】："Query User" called via CMD.exe results 0 Output

【发布时间】：2022-01-23 20:26:02

【问题描述】：

我正在尝试调用并收集 CMD 命令query user 返回的数据。

通过 cmd 从 Windows-startbar 调用它会给我一个正常的结果。

通过这个 c# 函数调用它会得到 0 输出。

     public void callQueryUser()
        
            ProcessStartInfo psi = new ProcessStartInfo("cmd.exe");
            Process p = Process.Start(psi);

            string cmd = string.Format(@"/c query user");
             
            psi.Arguments = cmd;
                                
            psi.RedirectStandardOutput = true;
            psi.UseShellExecute = false;
            psi.CreateNoWindow = true;
            psi.WaitForExit();
           
            string result = p.StandardOutput.ReadToEnd();
            MessageBox.Show(result);
        

我检查了，窗口说找不到命令...我还检查了它们是否都是相同的 cmd.exe，这也是正确的。似乎通过 C# 调用 cmd.exe 会有所不同。 有人知道我接下来可以检查什么吗？

【问题讨论】：

您没有等待进程退出 (process.WaitForExit())

@KlausGütter 抱歉，只是复制粘贴错误。当然，我在原始代码中等待退出。 Ty 试图提供帮助 :=)

您在 psiist 完全设置之前致电 Process.Start(psi)。当您将 Start 向下移动到 psi 完成时，它将起作用。

我想psi.WaitForExit() 应该是p.WaitForExit()

WMI 可能更适合这个

【参考方案1】：

不必使用cmd 来检索您想要使用Process 的信息。但是，如果您的操作系统是 64 位，您的程序以 32 位运行，并且您尝试访问 %windir%\System32\query.exe，则需要改用 %windir%\Sysnative\query.exe。

尝试以下方法：

选项 1：

public void callQueryUser()

    string queryPath = string.Empty;

    //use 'Sysnative' to access 64-bit files (in System32) if program is running as 32-bit process
    //use 'SysWow64' to access 32-bit files on 64-bit OS
    if (Environment.Is64BitOperatingSystem && !Environment.Is64BitProcess)
        queryPath = System.IO.Path.Combine(Environment.GetEnvironmentVariable("windir"), "Sysnative", "query.exe");
    else
        queryPath = System.IO.Path.Combine(Environment.GetEnvironmentVariable("windir"), "System32", "query.exe");

    Debug.WriteLine("queryPath: " + queryPath);

    // create new instance
    ProcessStartInfo startInfo = new ProcessStartInfo(queryPath);
    startInfo.Arguments = "user"; //arguments
    startInfo.CreateNoWindow = true; //don't create a window
    startInfo.RedirectStandardError = true; //redirect standard error
    startInfo.RedirectStandardOutput = true; //redirect standard output
    startInfo.UseShellExecute = false; //if true, uses 'ShellExecute'; if false, uses 'CreateProcess'
    startInfo.WindowStyle = ProcessWindowStyle.Hidden;

    //create new instance
    using (Process p = new Process  StartInfo = startInfo, EnableRaisingEvents = true )
    
        //subscribe to event and add event handler code
        p.ErrorDataReceived += (sender, e) =>
        
            if (!String.IsNullOrEmpty(e.Data))
            
                //ToDo: add desired code 
                Debug.WriteLine("Error: " + e.Data);
            
        ;

        //subscribe to event and add event handler code
        p.OutputDataReceived += (sender, e) =>
        
            if (!String.IsNullOrEmpty(e.Data))
            
                //ToDo: add desired code
                Debug.WriteLine("Output: " + e.Data);

                string result = e.Data;
                MessageBox.Show(result);
            
        ;

        p.Start(); //start

        p.BeginErrorReadLine(); //begin async reading for standard error
        p.BeginOutputReadLine(); //begin async reading for standard output

        //waits until the process is finished before continuing
        p.WaitForExit();
     

选项 2：

public void callQueryUser()

    string queryPath = string.Empty;

    //environment variable windir has the same value as SystemRoot
    //use 'Sysnative' to access 64-bit files (in System32) if program is running as 32-bit process
    //use 'SysWow64' to access 32-bit files on 64-bit OS
    if (Environment.Is64BitOperatingSystem && !Environment.Is64BitProcess)
        queryPath = System.IO.Path.Combine(Environment.GetEnvironmentVariable("windir"), "Sysnative", "query.exe");
    else
        queryPath = System.IO.Path.Combine(Environment.GetEnvironmentVariable("windir"), "System32", "query.exe");

    Debug.WriteLine("queryPath: " + queryPath);

    // create new instance
    ProcessStartInfo startInfo = new ProcessStartInfo(queryPath);
    startInfo.Arguments = "user"; //arguments
    startInfo.CreateNoWindow = true; //don't create a window
    startInfo.RedirectStandardError = true; //redirect standard error
    startInfo.RedirectStandardOutput = true; //redirect standard output
    startInfo.UseShellExecute = false; //if true, uses 'ShellExecute'; if false, uses 'CreateProcess'
    startInfo.WindowStyle = ProcessWindowStyle.Hidden;

    //create new instance
    using (Process p = new Process  StartInfo = startInfo, EnableRaisingEvents = true )
    
        p.Start(); //start

        //waits until the process is finished before continuing
        p.WaitForExit();

        string result = p.StandardOutput.ReadToEnd();
        MessageBox.Show(result);
    

资源：

Accessing files from System32 directory using 32 bit application on 64 bit machine Process Class ProcessStartInfo Class Environment.GetEnvironmentVariable Method

【讨论】：

先生，你是我的英雄