multithreading HELP

[blaze641983]

OK... here goes. I'm not new to VB.net, but I AM new to multi-threading.
Bust all you want about searching, but I hate reading hundreds of threads trying to find an answer to my problem when I don't really know what I'm searching for.

I need to pass information from a thread to my main thread. IE a progress bar value goes up as the thread makes progress..

I realize my code isn't the best, but I'll clean it up when I get it working faster.

By the way, there is a file write with append text. It's there as I was working on getting this program to move faster. I then discovered multi-threading and got stuck.

All critics on my code are welcome. I want to get better!

Imports System
Public Class frmMain
    Dim backThread1, backThread2, backThread3 As Threading.Thread
    Dim hexString1, hexString2, hexString3, finalString As String
    Dim FileRead As IO.StreamReader
    Dim FileWrite As IO.StreamWriter
    Dim FileName As String
    Dim hexCount
    Private Sub btnGenerate_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnGenerate.Click
        btnGenerate.Enabled = False
        backThread1 = New Threading.Thread(AddressOf Me.BackgroundWorks1)
        backThread2 = New Threading.Thread(AddressOf Me.BackgroundWorks2)
        backThread3 = New Threading.Thread(AddressOf Me.BackgroundWorks3)
        backThread1.Start()
    End Sub
 
    Private Sub btnClose_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClose.Click
        If backThread1.IsAlive Then
            backThread1.Abort()
        End If
        Me.Close()
    End Sub
 
    Private Sub frmMain_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        FileName = "C:\16-mil-hexcol.dat"
        ProgressBar1.Minimum = 0
        ProgressBar1.Maximum = 255
        ProgressBar1.Value = 0
        ProgressBar2.Minimum = 0
        ProgressBar2.Maximum = 255
        ProgressBar2.Value = 0
        ProgressBar3.Minimum = 0
        ProgressBar3.Maximum = 255
        ProgressBar3.Value = 0
    End Sub
 
    Private Sub BackgroundWorks1()
        Dim count1 As Integer = 0
        For count1 = 0 To 255
            hexCount = Hex(count1)
            hexString1 = Convert.ToString(hexCount)
            If count1 < 255 Then
                If Me.TextBox1.InvokeRequired Then
                    ' It's on a different thread, so use Invoke.
                    Dim d As New CallType
                    Me.Invoke(d, New Object() {[NewText] + " (Invoke)"})
                Else
                    ' It's on the same thread, no need for Invoke.
                    Me.TextBox1.Text = [NewText] + " (No Invoke)"
                End If
 
                ProgressBar1.Value += 1
            ElseIf count1 = 255 Then
                ProgressBar1.Value = 0
            End If
            Call BackgroundWorks2()
            FileWrite = IO.File.AppendText(FileName)
            FileWrite.Write(finalString)
            FileWrite.Close()
            finalString = ""
            hexString1 = ""
            hexString2 = ""
            hexString3 = ""
        Next count1
        FileRead = IO.File.OpenText(FileName)
        TextBox1.Text = FileRead.ReadToEnd()
        FileRead.Close()
    End Sub
 
    Private Sub BackgroundWorks2()
        Dim count2 As Integer = 0
        backThread2.Start()
        For count2 = 0 To 255
            hexCount = Hex(count2)
            hexString2 = Convert.ToString(hexCount)
            If count2 < 255 Then
                ProgressBar2.Value += 1
            ElseIf count2 = 255 Then
                ProgressBar2.Value = 0
            End If
            Call BackgroundWorks3()
        Next count2
    End Sub
 
    Private Sub BackgroundWorks3()
        Dim count3 As Integer = 0
        backThread3.Start()
        For count3 = 0 To 255
            hexCount = Hex(count3)
            hexString3 = Convert.ToString(hexCount)
            If hexString3.Length() <= 1 Then
                hexString3 = CStr("0" & hexString3)
            End If
            If hexString2.Length() <= 1 Then
                hexString2 = CStr("0" & hexString2)
            End If
            If hexString1.Length() <= 1 Then
                hexString1 = CStr("0" & hexString1)
            End If
            finalString &= CStr(hexString3 & " " & hexString2 & " " & hexString1 & " 00 ")
            If count3 < 255 Then
                ProgressBar3.Value += 1
            ElseIf count3 = 255 Then
                ProgressBar3.Value = 0
            End If
        Next count3
    End Sub
End Class