我如何从c#执行命令行程序,并获得STD OUT结果?具体来说,我想对两个以编程方式选择的文件执行DIFF,并将结果写入一个文本框。


当前回答

The accepted answer on this page has a weakness that is troublesome in rare situations. There are two file handles which programs write to by convention, stdout, and stderr. If you just read a single file handle such as the answer from Ray, and the program you are starting writes enough output to stderr, it will fill up the output stderr buffer and block. Then your two processes are deadlocked. The buffer size may be 4K. This is extremely rare on short-lived programs, but if you have a long running program which repeatedly outputs to stderr, it will happen eventually. This is tricky to debug and track down.

有一些很好的方法来处理这个问题。

One way is to execute cmd.exe instead of your program and use the /c argument to cmd.exe to invoke your program along with the "2>&1" argument to cmd.exe to tell it to merge stdout and stderr. var p = new Process(); p.StartInfo.FileName = "cmd.exe"; p.StartInfo.Arguments = "/c mycmd.exe 2>&1"; Another way is to use a programming model which reads both handles at the same time. var p = new Process(); p.StartInfo.FileName = "cmd.exe"; p.StartInfo.Arguments = @"/c dir \windows"; p.StartInfo.CreateNoWindow = true; p.StartInfo.RedirectStandardError = true; p.StartInfo.RedirectStandardOutput = true; p.StartInfo.RedirectStandardInput = false; p.OutputDataReceived += (a, b) => Console.WriteLine(b.Data); p.ErrorDataReceived += (a, b) => Console.WriteLine(b.Data); p.Start(); p.BeginErrorReadLine(); p.BeginOutputReadLine(); p.WaitForExit();

其他回答

一行运行命令:

new Process() { StartInfo = new ProcessStartInfo("echo", "Hello, World") }.Start();

以最短的可读代码量读取命令输出:

    var cliProcess = new Process() {
        StartInfo = new ProcessStartInfo("echo", "Hello, World") {
            UseShellExecute = false,
            RedirectStandardOutput = true
        }
    };
    cliProcess.Start();
    string cliOut = cliProcess.StandardOutput.ReadToEnd();
    cliProcess.WaitForExit();
    cliProcess.Close();

The accepted answer on this page has a weakness that is troublesome in rare situations. There are two file handles which programs write to by convention, stdout, and stderr. If you just read a single file handle such as the answer from Ray, and the program you are starting writes enough output to stderr, it will fill up the output stderr buffer and block. Then your two processes are deadlocked. The buffer size may be 4K. This is extremely rare on short-lived programs, but if you have a long running program which repeatedly outputs to stderr, it will happen eventually. This is tricky to debug and track down.

有一些很好的方法来处理这个问题。

One way is to execute cmd.exe instead of your program and use the /c argument to cmd.exe to invoke your program along with the "2>&1" argument to cmd.exe to tell it to merge stdout and stderr. var p = new Process(); p.StartInfo.FileName = "cmd.exe"; p.StartInfo.Arguments = "/c mycmd.exe 2>&1"; Another way is to use a programming model which reads both handles at the same time. var p = new Process(); p.StartInfo.FileName = "cmd.exe"; p.StartInfo.Arguments = @"/c dir \windows"; p.StartInfo.CreateNoWindow = true; p.StartInfo.RedirectStandardError = true; p.StartInfo.RedirectStandardOutput = true; p.StartInfo.RedirectStandardInput = false; p.OutputDataReceived += (a, b) => Console.WriteLine(b.Data); p.ErrorDataReceived += (a, b) => Console.WriteLine(b.Data); p.Start(); p.BeginErrorReadLine(); p.BeginOutputReadLine(); p.WaitForExit();

这可能不是最好/最简单的方法,但可能是一种选择:

当从代码执行时,添加“> output.txt”,然后读入output.txt文件。

 System.Diagnostics.ProcessStartInfo psi =
   new System.Diagnostics.ProcessStartInfo(@"program_to_call.exe");
 psi.RedirectStandardOutput = true;
 psi.WindowStyle = System.Diagnostics.ProcessWindowStyle.Hidden;
 psi.UseShellExecute = false;
 System.Diagnostics.Process proc = System.Diagnostics.Process.Start(psi); ////
 System.IO.StreamReader myOutput = proc.StandardOutput;
 proc.WaitForExit(2000);
 if (proc.HasExited)
  {
      string output = myOutput.ReadToEnd();
 }
// usage
const string ToolFileName = "example.exe";
string output = RunExternalExe(ToolFileName);

public string RunExternalExe(string filename, string arguments = null)
{
    var process = new Process();

    process.StartInfo.FileName = filename;
    if (!string.IsNullOrEmpty(arguments))
    {
        process.StartInfo.Arguments = arguments;
    }

    process.StartInfo.CreateNoWindow = true;
    process.StartInfo.WindowStyle = ProcessWindowStyle.Hidden;
    process.StartInfo.UseShellExecute = false;

    process.StartInfo.RedirectStandardError = true;
    process.StartInfo.RedirectStandardOutput = true;
    var stdOutput = new StringBuilder();
    process.OutputDataReceived += (sender, args) => stdOutput.AppendLine(args.Data); // Use AppendLine rather than Append since args.Data is one line of output, not including the newline character.

    string stdError = null;
    try
    {
        process.Start();
        process.BeginOutputReadLine();
        stdError = process.StandardError.ReadToEnd();
        process.WaitForExit();
    }
    catch (Exception e)
    {
        throw new Exception("OS error while executing " + Format(filename, arguments)+ ": " + e.Message, e);
    }

    if (process.ExitCode == 0)
    {
        return stdOutput.ToString();
    }
    else
    {
        var message = new StringBuilder();

        if (!string.IsNullOrEmpty(stdError))
        {
            message.AppendLine(stdError);
        }

        if (stdOutput.Length != 0)
        {
            message.AppendLine("Std output:");
            message.AppendLine(stdOutput.ToString());
        }

        throw new Exception(Format(filename, arguments) + " finished with exit code = " + process.ExitCode + ": " + message);
    }
}

private string Format(string filename, string arguments)
{
    return "'" + filename + 
        ((string.IsNullOrEmpty(arguments)) ? string.Empty : " " + arguments) +
        "'";
}