Storing variables generated by a while loop - arrays

Question

I have a while loop that parses a csv file, and inserts the variables into a series of arrays. This is called by a button on my main form.
These variables are used for a chart (which is in the same sub) and also for a datagrid, which is on a separate form.
The first time I click the button, everything works as normal, however if I click it a second time, the datagrid on the separate form is not populated, as I am losing the variables.
So within the while loop which parses the CSV file, I have this:
frmNumericChart.DataGridView1.Rows.Add(freq, dBu, dbnorm, ScaleFactor)
I have tried making the variables public, however because they are arrays, and constructed from the while loop, I can't seem to make them publicly accessible.
My code (edited for brevity)
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim sFile As String = strFileName
' get the minimum and maximum frequencies
Dim Lines As Collections.Generic.IEnumerable(Of String) = File.ReadLines(strFileName)
Dim Line0 As String = Lines.FirstOrDefault
Dim LineN As String = Lines.LastOrDefault
Dim lowestFreq As String() = Line0.Split(New Char() {","c})
Dim highestFreq As String() = LineN.Split(New Char() {","c})
Dim lowFreq As String = lowestFreq(0)
Dim highFreq As String = highestFreq(0)
Dim refFrequencyX = Lines(18)
Dim refFreq As String() = refFrequencyX.Split(New Char() {","c})
Dim ScaleFactor As String = refFreq(1)
Using sr As New StreamReader(sFile)
While Not sr.EndOfStream
Dim sLine As String = sr.ReadLine()
If Not String.IsNullOrWhiteSpace(sLine) Then
sData = sLine.Split(","c)
arrName.Add(sData(0).Trim())
arrValue.Add(sData(1).Trim())
End If
Dim freq As Decimal = sData(0)
Dim dBu As Decimal = sData(1)
Dim voltage As Decimal = sData(1)
' dbnorm - normalise output to 0dBu ref 1kHz
Dim dbnorm = Math.Round(dBu - ScaleFactor, 4)
frmNumericChart.DataGridView1.Rows.Add(freq, dBu, dbnorm, ScaleFactor)
Chart1.Series(0).Points.AddXY(freq, dbnorm)
End While
End Using
' ( chart is constructed here )
end sub
How can I make these array variables global?
Please excuse my shoddy code - I am doing this as a hobby and learning as I go along.

Answer 1

I solved this by adding a public class into a module.
Inside the 'Public Class' I have 'Public Shared Sub' for the subs I want access to from anywhere within the code.
Example:
Public Module Module1
<various public variables here>
Public Class MyData
Public Shared Sub debugTempFile()
' DEBUG
Dim mytempFolder As String = Path.GetTempPath()
Dim MyOutFile As String = mytempFolder + "outfile.txt"
Dim myfile As System.IO.StreamWriter
myfile = My.Computer.FileSystem.OpenTextFileWriter(MyOutFile, True)
myfile.WriteLine(debugdata)
myfile.Close()
' END DEBUG
End Sub
End Class
End Module
This Public Sub can be called from anywhere using the call statement:
Call MyData.debugTempFile()
I hope this is of use to other beginners like myself.