How to spawn a process and capture its STDOUT in .NET?
.net, c#, process, spawning
Solution
Here's code that I've verified to work. I use it for spawning MSBuild and listening to its output:
process.StartInfo.UseShellExecute = false;
process.StartInfo.RedirectStandardOutput = true;
process.OutputDataReceived += (sender, args) => Console.WriteLine("received output: {0}", args.Data);
process.Start();
process.BeginOutputReadLine();
Problem
I need to spawn a child process that is a console application, and capture its output. I wrote up the following code for a method: ``` string retMessage = String.Empty; ProcessStartInfo startInfo = new ProcessStartInfo(); Process p = new Process(); startInfo.CreateNoWindow = true; startInfo.RedirectStandardOutput = true; startInfo.RedirectStandardInput = true; startInfo.UseShellExecute = false; startInfo.Arguments = command; startInfo.FileName = exec; p.StartInfo = startInfo; p.Start(); p.OutputDataReceived += new DataReceivedEventHandler ( delegate(object sender, DataReceivedEventArgs e) { using (StreamReader output = p.StandardOutput) { retMessage = output.ReadToEnd(); } } ); p.WaitForExit(); return retMessage; ``` However, this does not return anything. I don't believe the `OutputDataReceived` event is being called back, or the `WaitForExit()` command may be blocking the thread so it will never callback. Any advice? EDIT: Looks like I was trying too hard with the callback. Doing: ``` return p.StandardOutput.ReadToEnd(); ``` Appears to work fine.