Public Class Form1
    Private Sub Button1_Click(sender As Object, e As EventArgs) Handles _
      Button1.Click
 
        Dim c1 As New Class1
        c1.pb = Me.ProgressBar1
        c1.Start()
 
    End Sub
 
    Private Sub Form1_Load(sender As Object, e As EventArgs) Handles MyBase.Load
        With ProgressBar1
            .Value = 0
            .Maximum = 20
        End With
    End Sub
End Class

Imports System.Threading
 
Public Class Class1
 
    Private _pb As ProgressBar
 
    Public Property pb As ProgressBar
        Get
            pb = _pb
        End Get
        Set(value As ProgressBar)
            _pb = value
        End Set
    End Property
 
    Public Sub Start()
        Dim trd As Threading.Thread
        trd = New Threading.Thread(AddressOf Beginnen)
        trd.Start()
    End Sub
 
    Private Sub Beginnen()
        For i As Integer = 1 To 20
 
            pb.BeginInvoke(Sub() pb.Value = i)
            Application.DoEvents()
            System.Threading.Thread.Sleep(500)
        Next
    End Sub
 
End Class

EALA FREYA FRESENA