Capturing console output from a .NET application (C#)


Question

How do I invoke a console application from my .NET application and capture all the output generated in the console?

(Remember, I don't want to save the information first in a file and then relist as I would love to receive it as live.)

1
119
8/12/2011 1:05:04 PM

Accepted Answer

This can be quite easily achieved using the ProcessStartInfo.RedirectStandardOutput property. A full sample is contained in the linked MSDN documentation; the only caveat is that you may have to redirect the standard error stream as well to see all output of your application.

Process compiler = new Process();
compiler.StartInfo.FileName = "csc.exe";
compiler.StartInfo.Arguments = "/r:System.dll /out:sample.exe stdstr.cs";
compiler.StartInfo.UseShellExecute = false;
compiler.StartInfo.RedirectStandardOutput = true;
compiler.Start();    

Console.WriteLine(compiler.StandardOutput.ReadToEnd());

compiler.WaitForExit();
155
8/12/2011 1:14:53 PM

This is bit improvement over accepted answer from @mdb. Specifically, we also capture error output of the process. Additionally, we capture these outputs through events because ReadToEnd() doesn't work if you want to capture both error and regular output. It took me while to make this work because it actually also requires BeginxxxReadLine() calls after Start().

using System.Diagnostics;

Process process = new Process();

void LaunchProcess()
{
    process.EnableRaisingEvents = true;
    process.OutputDataReceived += new System.Diagnostics.DataReceivedEventHandler(process_OutputDataReceived);
    process.ErrorDataReceived += new System.Diagnostics.DataReceivedEventHandler(process_ErrorDataReceived);
    process.Exited += new System.EventHandler(process_Exited);

    process.StartInfo.FileName = "some.exe";
    process.StartInfo.Arguments = "param1 param2"
    process.StartInfo.UseShellExecute = false;
    process.StartInfo.RedirectStandardError = true;
    process.StartInfo.RedirectStandardOutput = true;

    process.Start();
    process.BeginErrorReadLine();
    process.BeginOutputReadLine();          

    //below line is optional if we want a blocking call
    //process.WaitForExit();
}

void process_Exited(object sender, EventArgs e)
{
    Console.WriteLine(string.Format("process exited with code {0}\n", process.ExitCode.ToString()));
}

void process_ErrorDataReceived(object sender, DataReceivedEventArgs e)
{
    Console.WriteLine(e.Data + "\n");
}

void process_OutputDataReceived(object sender, DataReceivedEventArgs e)
{
    Console.WriteLine(e.Data + "\n");
}

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