C # coding convention public / private contexts

Question

I am learning C # and I am creating a simple WinForms application, and what it does is launching a simple OpenVPN client:

    void button_Connect_Click(object sender, EventArgs e)
    {
        var proc = new Process();
        proc.StartInfo.FileName = "CMD.exe";
        proc.StartInfo.UseShellExecute = false;
        proc.StartInfo.WorkingDirectory = @"C:\Program Files (x86)\OpenVPN\bin";
        proc.StartInfo.Arguments = "/c openvpn.exe --config config.ovpn --auto-proxy";

        // set up output redirection
        proc.StartInfo.RedirectStandardOutput = true;
        proc.StartInfo.RedirectStandardError = true;
        // Input
        proc.StartInfo.RedirectStandardInput = true;

        // Other
        proc.EnableRaisingEvents = true;
        proc.StartInfo.CreateNoWindow = false;
        // see below for output handler
        proc.ErrorDataReceived += proc_DataReceived;
        proc.OutputDataReceived += proc_DataReceived;

        proc.Start();

        StreamWriter myStreamWriter = proc.StandardInput;
        proc.BeginErrorReadLine();
        proc.BeginOutputReadLine();

        proc.WaitForExit();
    }

    void proc_DataReceived(object sender, DataReceivedEventArgs e)
    {
        // output will be in string e.Data
        if (e.Data != null)
        {
            string Data = e.Data.ToString();
            if (Data.Contains("Enter Auth Username"))
            {
                myStreamWriter("myusername");
            }
            //MessageBox.Show(Data);
        }
    }

Now it sends all CMD output to my program, which run commands depending on the output.

My current problem: I need to write to the stream. I use myStreamWriterin proc_DataReceived, however it is not in the same context, so it does not work.

I get the following error: The name 'myStreamWriter' does not exist in the current contextwhich clearly does not exist in this area.

How do I do this job? Get / set properties? As I said, I am new to C #, so any help is appreciated.

Answer 1

:

public class Form1Whatevver: Form {
    private StreamWriter myStreamWriter;
}

:

proc.Start();

this.myStreamWriter = proc.StandardInput;

proc.BeginErrorReadLine();
proc.BeginOutputReadLine();

myStreamWriter proc_DataReceived()

void proc_DataReceived(object sender, DataReceivedEventArgs e)
    {
        // output will be in string e.Data
        if (e.Data != null)
        {
            string Data = e.Data.ToString();
            if (Data.Contains("Enter Auth Username"))
            {
                if (myStreamWriter != null) // Just in case
                {
                    myStreamWriter("myusername");
                }
            }
            //MessageBox.Show(Data);
        }
    }

Answer 2

, , Scope .

---

, myStreamWriter proc_DataReceived.

, - , . .

    void proc_DataReceived(
        object sender, 
        DataReceivedEventArgs e,
        StreamWriter writer)
    {
        ...
        writer("myusername");
        ...
    }

proc_DataReceived, , , , , .

---

myStreamWriter , . this , .

class YourForm : Form
{
    private StreamWriter myStreamWriter;

    void button_Connect_Click(...
    {
        ...
        this.myStreamWriter = proc.StandardInput;
        ...
    }

    void proc_DataRecieved(...
    {
        ...
        this.myStreamWriter("myusername");
        ...

    }
}

---

, StreamWriter /.

Answer 3

A simple quick fix is ​​to determine myStreamWriterhow the field is in the class (i.e. outside the scope of your methods), and then create an instance from one of the areas:

private StreamWriter _myStreamWriter;

void button_Connect_Click(object sender, EventArgs e)
{
    // Do some stuff

    _myStreamWriter = proc.StandardInput;

    // Do some stuff
}

Having done this, you should use it wherever you want in the class.