serial port data plotting on ZedGraph

Imports ZedGraph
Imports System.IO.Ports
Imports System.Threading


Public Class Form1
    Public data As Integer
    Public data_buffer(4) As Integer
    Public data_store As Integer
    
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        SetSize()
    End Sub

    Public Sub CreateGraph(ByVal zgc As ZedGraphControl)
        Dim myPane As GraphPane = zgc.GraphPane

        ' Set the titles and axis labels
        myPane.Title.Text = "My Test Date Graph"
        myPane.XAxis.Title.Text = "X Value"
        myPane.YAxis.Title.Text = "My Y Axis"

        ' Make up some data points from the Sine function
        Dim list = New PointPairList()
        Dim x As Integer, y As Integer
        For x = 0 To 100
        Next x
       
        y = data_buffer(1)
        list.Add(x, y)


        ' Generate a blue curve with circle symbols, and "My Curve 2" in the legend
        Dim myCurve As LineItem = myPane.AddCurve("My Curve", list, Color.Blue, SymbolType.None)

        ' Fill the area under the curve with a white-red gradient at 45 degrees
        myCurve.Line.Fill = New Fill(Color.White, Color.Red, 45.0F)

        ' Make the symbols opaque by filling them with white
        myCurve.Symbol.Fill = New Fill(Color.White)

        ' Fill the axis background with a color gradient
        myPane.Chart.Fill = New Fill(Color.White, Color.LightGoldenrodYellow, 45.0F)

        ' Fill the pane background with a color gradient
        myPane.Fill = New Fill(Color.White, Color.FromArgb(220, 220, 255), 45.0F)

        ' Calculate the Axis Scale Ranges
        zgc.AxisChange()
    End Sub

    Private Sub Form1_Resize(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Resize
        SetSize()
    End Sub

    Private Sub SetSize()
        zg1.Location = New Point(10, 10)
        ' Leave a small margin around the outside of the control
        zg1.Size = New Size(ClientRectangle.Width - 20, ClientRectangle.Height - 20)
    End Sub

    Private Sub cmd_open_port(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Try
            If SerialPort1.IsOpen = False Then
                SerialPort1.Open()
            End If
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try

    End Sub
    Private Sub DataReceived(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles SerialPort1.DataReceived
        Do
            Try
                data = SerialPort1.ReadByte ' read first byte and check if it is 64
            Catch ex As Exception
                MessageBox.Show(ex.Message)
            End Try

        Loop While (data <> 64) 'if data is 64 (new frame starts) , so come out of the loop and start reading and storing data in an array

        data_buffer(0) = data ' 64 is stored inside the databuffer


        data = SerialPort1.ReadByte  'data is read from serialport 
        data_buffer(1) = data ' push data to buffer

        Me.Invoke(New EventHandler(AddressOf UpdateControl))
        data = SerialPort1.ReadByte  '  * data 
        data_buffer(2) = data ' push to buffer
        
        data = SerialPort1.ReadByte  ' CHECKSUM 
        data_buffer(3) = data ' push to buffer


        data = SerialPort1.ReadByte ' CHECKSUM 
        data_buffer(4) = data ' push to buffer
        Dim i As Integer
        For i = 0 To 4
            Console.WriteLine(data_buffer(i))
        Next

    End Sub

    Public Sub UpdateControl(ByVal sender As Object, ByVal e As EventArgs)

        'Do any UI code here on the main thread
        CreateGraph(zg1)

    End Sub

  
End Class