Drawing a zedgraph by using serial port data

BackgroundWorker worker;
List<float> measures;
public Form1()
{
    InitializeComponent();

    measures = new List<float>();

    worker = new BackgroundWorker();
    worker.DoWork += (sender, e) =>
    {
        //put all your serial port code here
        ...

        //when you want to update the measures list
        lock (measures)
        {
            measures.Add(...);
        }

        //sometimes update the graph
        BeginInvoke((Action)(() =>
        {
            lock (measures)
            {
                //fill your PointPairList from the measures
                ...
            }
            zedGraphControl1.AxisChange();
            zedGraphControl1.Invalidate();
        }));
    };
}
private void button1_Click(object sender, EventArgs e)
{
    //starts the worker
    worker.RunWorkerAsync();
}

    public partial class Form1 : Form
    {
        /// List of double: do not forget the <double>!!
        /// This is a the list of the new measures since the last update
        List<double> measures;
        /// The ZedGraph curve
        LineItem myCurve;
        BackgroundWorker worker;
        public Form1()
        {
            InitializeComponent();
            //create an empty list
            measures = new List<double>();
            //init your zegGraphControl here
            ...
            //create an empty curve: it will be filled later
            myCurve = myPane.AddCurve("Porsche", null, Color.Red, SymbolType.Diamond);
            //create the worker
            worker = new BackgroundWorker();
            // set this to true so that you can cancel the worker
            worker.SupportsCancellation = true;
            worker.DoWork += worker_DoWork;
            worker.RunWorkerCompleted += worker_RunWorkerCompleted;
        }
        private void button1_Click(object sender, EventArgs e)
        {
            //start the worker
            worker.RunWorkerAsync();
        }
        private void button2_Click(object sender, EventArgs e)
        {
            //stop the worker
            worker.CancelAsync();
        }
        private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)
        {
            //the worker has completed
            //do whatever you want here
            ...
        }
        private worker_DoWork(object sender, DoWorkEventArgs e)
        {
            //put all your serial port code here
            SerialPort sprt = new SerialPort("COM3");
            sprt.BaudRate = 9600;
            sprt.Parity = Parity.None;
            sprt.StopBits = StopBits.One;
            sprt.DataBits = 8;
            sprt.Handshake = Handshake.None;
            try
            {
                sprt.Open();
            }
            catch (Exception)
            {
                MessageBox.Show("Check port");
                return;
            }
            //worker.CancellationPending will change to true when CancelAsync is called
            //(so when the user clicks button2).
            //while the worker should still continue, read incoming data
            while (!worker.CancellationPending)
            {
                //wait for data to come...
                System.Threading.Thread.Sleep(100);
                string indata = sprt.ReadExisting();
                //extract the values from the read data
                //be careful here: make sure the read data is complete...
                string[] splt = indata.Split(':');
                string chop = splt[2];
                string final = chop.Remove(5);
                float d = Convert.ToSingle(final);
                //update the measures
                //measures is shared by several threads: you must lock it to access it safely
                lock (measures)
                {
                    measures.Add(d);
                }
                //update the graph
                BeginInvoke((Action)(() => UpdateGraph()));
            }
            //user wants to stop the worker
            sprt.Close();
        }
        /// This function is called when the graph should be updated
        private void UpdateGraph()
        {
            //messures is shared by several threads: you must lock it to access it safely
            lock (measures)
            {
                //add each measure into the curve
                for (int i = 0; i < measures.Count; i++)
                {
                    //fill each with what ever you want
                    double x = myCurve.Points.Count;
                    double y = measures[i];
                    //add a new point to the curve
                    myCurve.AddPoint(x, y);
                }
                //all measures have been added
                //we can empty the list
                measures.Clear();
            }
            //the curve has been updated so refresh the graph
            zedGraphControl1.AxisChange();
            zedGraphControl1.Invalidate();
        }
    }
</double>