C# Process.StandardOutput.ReadLine() 挂起

Question

所以基本上 ReadLine() 方法就挂在最后一行。

我不需要结束进程。主要目标是使用 stdin 和 stdout（in variables/Printed out）执行“cmd-shell”。

如果用异步方法也能达到同样的效果，请在评论中留下。提前致谢。

        {
            Process p = new Process()
            {
                StartInfo = new ProcessStartInfo("cmd")
                {
                    UseShellExecute = false,
                    RedirectStandardInput = true,
                    RedirectStandardError = true,
                    RedirectStandardOutput = true,
                    CreateNoWindow = true,
                    Arguments = "/K",
                    
                }
            };
            p.ErrorDataReceived += (s, e) =>
            {
                if (!string.IsNullOrEmpty(e.Data))
                {
                    Console.WriteLine(e.Data);
                }
            };
            p.Start();
            while (true)
            {
                Console.Write("/SHELL/ #> ");
                input = Console.ReadLine();
                p.StandardInput.WriteLine(input);
                p.BeginErrorReadLine();
                Console.WriteLine("Errorgoing...");
                while (p.StandardOutput.Peek() > -1) {
                    Console.WriteLine(p.StandardOutput.Peek());
                    Console.WriteLine(p.StandardOutput.ReadLine());
                    
                    // When it hangs, Peek() outputs 67, that represents "C" char.
                    // Seems like just the last stdout line dont want to be printed out.
                }
            }
        }
    }```

Answer 1

在实施了一些技巧之后，我得到了以下代码。相当棘手。

static async Task Main(string[] args)
{
    using (SemaphoreSlim semaphore = new SemaphoreSlim(0, 1))
    {
        Process p = new Process()
        {
            StartInfo = new ProcessStartInfo("cmd")
            {
                UseShellExecute = false,
                RedirectStandardInput = true,
                RedirectStandardError = true,
                RedirectStandardOutput = true,
                CreateNoWindow = true,
                Arguments = "/K set PROMPT=PROMPT$P$G$_",
            }
        };
        p.ErrorDataReceived += (s, e) =>
        {
            if (e.Data?.Length > 0)
            {
                Console.WriteLine(e.Data);
            }
        };
        bool wasprompt = false;
        string prompt = "";
        p.OutputDataReceived += (s, e) =>
        {
            if (e.Data?.Length > 0)
            {
                if (e.Data.StartsWith("PROMPT") && e.Data.EndsWith(">"))
                {
                    prompt = e.Data.Substring(6, e.Data.Length - 7);
                    semaphore.Release();
                    wasprompt = true;
                }
                else
                {
                    if (!wasprompt)
                        Console.WriteLine(e.Data);
                    else
                        wasprompt = false;
                }
            }
        };
        p.Start();
        p.BeginErrorReadLine();
        p.BeginOutputReadLine();
        await semaphore.WaitAsync();
        while (!p.HasExited)
        {
            Console.Write($"/SHELL/ {prompt}#> ");
            string input = Console.ReadLine();
            p.StandardInput.WriteLine(input);
            if (input == "exit") break;
            await semaphore.WaitAsync();
        }
        p.WaitForExit();
    }

    Console.WriteLine("Bye.");
    Console.ReadKey();
}

经过几次测试，看起来像您期望的那样工作。

想法是将 $_ 添加到 PROMPT 环境变量以强制打印提示以输出。然后我抓住那个提示并实现 input/output 与 SemaphoreSlim 同步。

C# Process.StandardOutput.ReadLine() 挂起

C# Process.StandardOutput.ReadLine() hangs

c#

process

synchronous