Process.Exitcode returns wrong value

Posted on 2013-11-15
Last Modified: 2013-11-19
I've written a C# class that calls a DOS application in the context of a Process. The problem is that Process.Exitcode always returns 0 indicating success even if the DOS program fails. I've run this DOS application in a batch file from a command prompt, and I know it returns an error code. Here's my setup for the process:

        public void Start()
            m_isDone = false;
            m_result = 0;
            m_isStandardOutputDone = false;
            m_isErrorOutputDone = false;
            m_consoleProcess = new Process();
            m_consoleProcess.StartInfo.FileName = m_command;
            m_consoleProcess.StartInfo.Arguments = m_commandArguments;
            m_consoleProcess.StartInfo.UseShellExecute = false;
            m_consoleProcess.StartInfo.CreateNoWindow = true;
            m_consoleProcess.StartInfo.RedirectStandardOutput = true;
            m_consoleProcess.StartInfo.RedirectStandardError = true;
            m_consoleProcess.OutputDataReceived += StandardOutputEventHandler;
            m_consoleProcess.ErrorDataReceived += ErrorOutputEventHandler;

And the standard output event handler:

        private void StandardOutputEventHandler(object sendingProcess, DataReceivedEventArgs eventArgs)
            String output = eventArgs.Data;
            if ( !String.IsNullOrEmpty(output) )
                // Notify standard output event subscribers that there's new text.
                StandardOutputEvent(this, eventArgs);
            if ( (output == null) && m_consoleProcess.HasExited )
                m_isStandardOutputDone = true;

                if ( m_isErrorOutputDone && !m_isDone )
                    // Signal process completion.
                    m_isDone = true;
                    m_result = m_consoleProcess.Exitcode;
                    EventArgs e = new EventArgs();
                    if ( ProcessDoneEvent != null )
                        ProcessDoneEvent(this, e);

It's here in the standard output event handler that I determine whether the process has completed and record the exit code. This works well, except that the exit code doesn't represent the correct output of the DOS program. How do I obtain the correct exit code?
Question by:alconlabs
  • 3
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LVL 96

Expert Comment

by:Bob Learned
ID: 39653357
It doesn't look like you are waiting for the process to end, so the ExitCode won't be set yet.

Author Comment

ID: 39653940
m_consoleProcess.HasExited is true, so I assume the process has ended. The documentation for HasExited would seem to imply that if HasExited is true, it's safe to query the ExitCode and ExitTime properties, no?
LVL 96

Accepted Solution

Bob Learned earned 500 total points
ID: 39653964
As a test, you can try Process.WaitForExit, and see if the ExitCode is set.
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LVL 23

Expert Comment

by:Ioannis Paraskevopoulos
ID: 39654127
I think you could store the exit code of the DOS app, and just 'return' it from your main sub.

Author Comment

ID: 39661333
WaitForExit didn't return, and the event handler for the Exited event didn't fire. Turns out I need to set EnableRaisingEvents to get these to work (though OutputDataReceived and ErrorDataReceived events work just fine without it). I'll give the points to TheLearnedOne since he got me headed down the right path.
LVL 96

Expert Comment

by:Bob Learned
ID: 39661340
Aah, yes, the needle-in-the-haystack...glad you found it.

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