More than one problem. First off, as @shf301 already told you, you forgot to read stderr. He in turn forgot to add an extra line:
Process.Start()
AddHandler Process.OutputDataReceived, _
Sub(processSender As Object, lineOut As DataReceivedEventArgs)
output += lineOut.Data + vbCrLf
End Sub
Process.BeginOutputReadLine()
AddHandler Process.ErrorDataReceived, _
Sub(processSender As Object, lineOut As DataReceivedEventArgs)
output += lineOut.Data + vbCrLf
End Sub
Process.BeginErrorReadLine()
There’s another very cumbersome problem, your event handlers run late. They fire after the process has already exited. A side effect of these handlers running on a thread-pool thread. You’ll need to wait for an arbitrary (and unguessable) amount of time before you use the output variable:
Do
Application.DoEvents()
Loop Until Process.HasExited
System.Threading.Thread.Sleep(1000)
This is too ugly. Do this the way that any IDE or editor does it. Redirect the output to a temporary file and read the file afterwards:
Dim tempfile As String = System.IO.Path.GetTempFileName
Using Process As New Process
Process.StartInfo = New ProcessStartInfo("cmd.exe")
Process.StartInfo.Arguments = "/c make 1> """ + tempfile + """ 2>&1"
Process.StartInfo.WorkingDirectory = "C:\projectTest"
Process.StartInfo.UseShellExecute = False
Process.StartInfo.CreateNoWindow = True
Process.Start()
Process.WaitForExit()
output = System.IO.File.ReadAllText(tempfile)
System.IO.File.Delete(tempfile)
End Using
Some annotation with the mystic command line:
- /c tells cmd.exe to execute just the single command and then exit
- 1> redirects the output to the temporary file
- 2>&1 tells cmd.exe to redirect stderr to stdout
- the triple double quotes ensures that spaces in the tempfile name don’t cause trouble.
That same 2>&1 would also have fixed your original problem 😉