How can I access a variable in a private void?

Question

I have a windows application that sends and receives messages to/from a microprocessor using the serial port.

The application is working fine and does what is supposed to do. Now, I need to make some elaboration with the data I receive back from serial and I would like to access the variable "value" in SetText method. How can I access the content of that variable from another method or class? Thanks for helping.

delegate void SetTextCallback(string text);

    private void SetText(string text)

    {

        if (this.txtOutput.InvokeRequired)

        {

            SetTextCallback d = new SetTextCallback(SetText);

            this.BeginInvoke(d, new object[] { text });

        }

        else

        {

            txtOutput.AppendText(text);

        }

        // capture messages from serial port

        if (txtOutput.Text.Length > 0)

        {

            MatchCollection mc = Regex.Matches(txtOutput.Text, @"(\+|-)?\d+");

            if (mc.Count > 0)

            {

                long value = long.Parse(mc[mc.Count - 1].Value);

                if (value > 1 && value < 1000)

                {

                    textBox2.Text = value.ToString();

                }

                else if (value < 2000 && value > 1000)

                {

                    value = value - 1000;

                    textBox3.Text = value.ToString();

                }

            }

        }

    }

    private void serialPort1_DataReceived(object sender, System.IO.Ports.SerialDataReceivedEventArgs e)

    {

        try

        {

            SetText(serialPort1.ReadExisting());

        }

        catch (Exception ex)

        {

            SetText(ex.ToString());

        }

    }