Visual Basic

Imports System.Drawing.Drawing2D
Imports System.IO.Ports

Public Class Form1
    Dim bmp1 As Bitmap = New Bitmap(165, 550)
    Dim temperature1 As Double = 10
    Dim temperature2 As Double = 10
    Dim WithEvents sp As New SerialPort

    Private Sub pictherm1_Paint(ByVal sender As System.Object, ByVal e As System.Windows.Forms.PaintEventArgs) Handles pictherm1.Paint
        Dim g As Graphics = e.Graphics
        g.Clear(Color.White)
        ' fill temperature1
        If temperature1 > 100 Then temperature1 = 100
        g.FillRectangle(Brushes.Green, 48, 525 - CInt(temperature1 * 5), 10, CInt(temperature1 * 5))
        ' fill temperature2
        If temperature2 > 100 Then temperature2 = 100
        g.FillRectangle(Brushes.Green, 108, 525 - CInt(temperature2 * 5), 10, CInt(temperature2 * 5))
        'draw scale
        g.DrawLine(Pens.Black, 60, 525, 60, 25)
        g.DrawLine(Pens.Black, 105, 525, 105, 25)
        ' minor ticks
        For i As Integer = 25 To 525 Step 5
            g.DrawLine(Pens.Black, 50, i, 60, i)
            g.DrawLine(Pens.Black, 105, i, 115, i)
        Next
        'major ticks
        Dim f As Font = New Font("Verdana", 10, FontStyle.Regular)
        Dim scale As Integer
        For i As Integer = 525 To 25 Step -25
            g.DrawLine(Pens.Black, 45, i, 60, i)
            g.DrawLine(Pens.Black, 105, i, 120, i)
            scale = (525 - i) / 5
            g.DrawString(Str(scale), f, Brushes.Black, 65, i - 8)
        Next
    End Sub

    Private Sub btnConnect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnConnect.Click
        Try
            sp.BaudRate = "9600"
            sp.PortName = "COM5"
            sp.Open()
            If sp.IsOpen Then
                btnConnect.Visible = False
                btnDisconnect.Visible = True
            End If
        Catch
            sp.Close()
        End Try
    End Sub

    Private Sub Form1_FormClosing(ByVal sender As System.Object, ByVal e As System.Windows.Forms.FormClosingEventArgs) Handles MyBase.FormClosing
        If sp.IsOpen() Then
            MessageBox.Show("Disconnect before closing")
            e.Cancel = True
        End If
    End Sub

    Delegate Sub myMethodDelegate1(ByVal [text] As String)
    Dim myDelegate1 As New myMethodDelegate1(AddressOf ProcessReading1)

    Private Sub SerialPort_DataReceived1(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles sp.DataReceived
        Dim str1 As String = sp.ReadLine()
        Dim firststr As String = Mid(str1, 1, 4)
        Invoke(myDelegate1, firststr)
    End Sub

    Sub ProcessReading1(ByVal input As String)
        If IsNumeric(input) Then
            temperature1 = CDbl(input)
            lblLeft.Text = CDbl(temperature1)
            pictherm1.Refresh()
        End If
    End Sub

    Delegate Sub myMethodDelegate2(ByVal [text] As String)
    Dim myDelegate2 As New myMethodDelegate2(AddressOf ProcessReading2)

    Private Sub SerialPort_DataReceived2(ByVal sender As Object, ByVal e As System.IO.Ports.SerialDataReceivedEventArgs) Handles sp.DataReceived
        Dim str2 As String = sp.ReadLine()
        Dim secondstr As String = Mid(str2, 6, 5)
        Invoke(myDelegate2, secondstr)
    End Sub

    Sub ProcessReading2(ByVal input As String)
        If IsNumeric(input) Then
            temperature2 = CDbl(input)
            lblRight.Text = CDbl(temperature2)
            lblTotal.Text = CDbl(temperature1 + temperature2)
            lblDiff.Text = CDbl(temperature1 - temperature2)
            pictherm1.Refresh()
        End If
    End Sub

    Private Sub btnDisconnect_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnDisconnect.Click
        Try
            sp.Close()
            btnConnect.Visible = True
            btnDisconnect.Visible = False
            Exit Sub
        Catch
            MessageBox.Show("Some kind of problem.")
        End Try
    End Sub

End Class

Premise that I do not have much experience with visual basic!
I need to make a chart from a csv file that is structured like this:

"VarName", "TimeString", "Temperature", "Validity", "Time_ms"
"var_1", "04/02/2014 04:40:29", 115.5, 1, 41,731,194,780.0926
"var_3", "04/02/2014 04:42:37", 27.4, 1, 41,731,196,261.5741
"var_2", "04/02/2014 04:42:37", 83.2, 1, 41,731,196,261.5741
"var_1", "04/02/2014 04:42:37", 115.8, 1, 41,731,196,261.5741

note that "VarName" are listed in no particular order.
What I would like is to be able to choose the "VarName" via a ComboBox and via a DateTimePicker the day, so as to produce a chart with "TimeString" on the X axis and "Temperature" on Y.
If can be done you can help me, I dont know where to start.
Sorry for my english :-O 
Thank you!

Public Function CenterMessageBox(ByRef frmHwnd As Integer) As Object
        '******************************
        'WARNING: NOT FOLLOWING BELOW INSTRUCTIONS EXACTLY
        'COULD CRASH YOUR APPLICATION

        'INSTRUCTIONS:

        '1. YOU MUST PUT ALL THIS CODE IS A .BAS MODULE

        '2. YOU CALL THIS CODE IMMEDIATELY BEFORE DISPLAYING A MSGBOX,

        '3.  PASS IN THE hWnd Property of Form as parameter

        'Example:

        'CenterMessageBox me.hwnd
        'MsgBox "This is a centered Message Box"
        '*********************************
        Dim lInstance As Integer
        Dim lThreadID As Integer

        'Set up message hook
        lInstance = GetWindowLong(frmHwnd, GWL_HINSTANCE)
        lThreadID = GetCurrentThreadId()
        'UPGRADE_WARNING: Add a delegate for AddressOf CenterMsgCallBack Click for more: 'ms-help://MS.VSCC.v80/dv_commoner/local/redirect.htm?keyword="E9E157F7-EF0C-4016-87B7-7D7FBBC6EE08"'
        plMsgHook = SetWindowsHookEx(WH_CBT, AddressOf CenterMsgCallBack, lInstance, lThreadID)

    End Function

Private Function CenterMsgCallBack(ByVal lMsg As Integer, ByVal wParam As Integer, ByVal lParam As Integer) As Integer

        Dim typFormRect As RECT
        Dim typRectMsg As RECT
        Dim lxPos, lyPos As Integer

        'HCBT_ACTIVATE = MSG SENT WHEN MSGBOX IS ACTIVATED
        'wParam = handle to msgbox
        If lMsg = HCBT_ACTIVATE Then
            'resolve center of form

            'form rectangle
            GetWindowRect(frmMain.Handle.ToInt32, typFormRect)

            'msgbox rectangle
            GetWindowRect(wParam, typRectMsg)

            'Determine x and y
            lxPos = (typFormRect.Left_Renamed + (typFormRect.Right_Renamed - typFormRect.Left_Renamed) / 2) - ((typRectMsg.Right_Renamed - typRectMsg.Left_Renamed) / 2)

            lyPos = (typFormRect.Top + (typFormRect.Bottom - typFormRect.Top) / 2) - ((typRectMsg.Bottom - typRectMsg.Top) / 2)

            'Position
            SetWindowPos(wParam, 0, lxPos, lyPos, 0, 0, SWP_NOSIZE Or SWP_NOZORDER Or SWP_NOACTIVATE)

            'Release the hook
            UnhookWindowsHookEx(plMsgHook)
        End If

        CenterMsgCallBack = False

    End Function