Question

I guess you all misunderstood my question and closed it at How to run a Command in C# and retrieve data from it?

I had said in that post also :-
want to run a Command from command promt and want its output and maipulate its output. If required, want to close the process and display error or appropriate message. To stop the process, I have to press “F4′ key on command prompt. Till the process is stopeed or killed, it has to be alive only.

I have created a class to handle running the cmd. And I keep getting the output. But on reading the output’s each line I want to stop or throw exception if found anything improper in the output.

I am tying to connect to server via cmd. Server keeps on giving output. Suppose the server gave output as :
Trying to start …..
Cananot load file
…..
Exiting

While retrieving the output, I want to check for lines like “Cannot find file”, “Connected Successfully, etc and set properties ccordingly (like connected = true, errorMsg = “Cannot find file”. Where I am calling the class, I can take care of those proeprties and stop if found connected == true or errorMsg.length > 0. With this inform the user that “Connection is achieved or error msg stating regarding “Cannot load file” and disconnect the server if errorMsg found.

I didn’t find anywhere doing any manipulation on the output receving and that’s where I find myself stuck. I found a lot on internet. Am stuck and trying to figre out this part from last 3-4 days. Then have posted here.

I need help in that. Please help me. If requiried I will psot code snippets. But please help me. AND don’t close this thread as answered ithout understanding my question fully. This is no duplicate.

My code is class :

    public int ConnectToServer()
    {
        int error = 0;
        connected = false;
        try
        {
            process = Process.Start(processInfo);

            process.BeginOutputReadLine();
            process.OutputDataReceived += new DataReceivedEventHandler(Process_OutputDataReceived);
            //if (errorMsg.Length > 0)
            //    throw new Exception(errorMsg);
        }
        catch (Exception e)
        {
            Console.WriteLine("Error Processing ConnectToServer : " + e.Message);
            connected = false;
            errorMsg = e.Message;
            error = -1;
            return error;
        }

        return error;
    }

    private void Process_OutputDataReceived(object sender, DataReceivedEventArgs e)
    {
        errorMsg = "";
        connected = false;
        string d = e.Data;

        if (!string.IsNullOrEmpty(d))
        {
            if (sb != null)
                sb.Append(d + "\n");
            Console.WriteLine("LINE = " + d);
            if (d.IndexOf("Initialization Completed") > 0)
            {
                connected = true;
                Console.WriteLine("********* Connected = " + connected);
            }
            else if (isInValidLine(d))
            {
                //throw new Exception(d);
                connected = false;
                errorMsg = d;
                return;
            }
                            }
        return;
    }

    private bool isInValidLine(string line)
    {
        if (line.IndexOf("Cannot load file") > 0)
        {
            errorMsg = line;
            return true;
        }
        return false;
    }   

IS THE ABOVE CLASS CODE CORRECT WITH MY REQUIREMENTS ?
In impementation :

        while (!oc.Connected)
        {
            timepassed = (int)(DateTime.Now - start).TotalMilliseconds;
            if (timepassed > timeout)
            {
                oc.DisconnectServer();
                connectedToVpn = false;
                throw new Exception("NotConnectedException");
            } else if (oc.ErrorMessage.Length > 0)
            {
                oc.DisconnectServer();
                connectedToVpn = false;
                throw new Exception(oc.ErrorMessage);
            }
            Thread.Sleep(100);
        }   

Here what I am doing is, when I get the output line, I check if it states as Conneced or is invalid. If its invalid, I set the line as the errorMsg. In my while loop I keep chekcing for Connected and errorMessage, but the value of errorMessage stays as “” only. It never gets updated, which tell me that the processing output code is never executed. Nor in debug mode I find the cursor at that line, but the Line = is displayed proeprly in Console. So, don’t understand what’s going wrong and where.

Hope this helps you more understand.

Thanks

Answer 1

once you have redirected the standard output of the process you have executed you could parse what you receive as it arrives, I believe also line by line, then you can post commands to control your process.

to read output you have redirected the standard output, to send input you should also redirect the standard input of the process.