Command prompt output being read as empty string

Question

I\'m trying to execute command prompt commands and read the output in C#. This is my code:

ProcessStartInfo cmdInfo = new ProcessStartInfo(\"cmd.exe\", \"/c          


        

Answer 1

Not all output is written to StandardOutput; many applications will instead write to StandardError if something goes wrong. You would have to read from both to get all of the output.

As long as the application never blocks for input, it should be safe to call ReadToEnd() on both output streams to get all of the output. A safer option, however, is to hook up an event to the OutputDataReceived and ErrorDataReceived events. You can attach lambda expression to these that close over local variables to make things pretty simple:

var output = new StringBuilder();
var error = new StringBuilder();

cmd.OutputDataReceived += (o, e) => output.Append(e.Data);
cmd.ErrorDataReceived += (o, e) => error.Append(e.Data);

cmd.Start();
cmd.BeginOutputReadLine();
cmd.BeginErrorReadLine();
cmd.WaitForExit();