Public Class CThreadGen
    Public testThread As Threading.Thread
    Public Event ProcMsg(ByVal msgText As String)
 
    Public Sub StartThread()
        testThread = New Threading.Thread(AddressOf Run)
        testThread.Start()
    End Sub
 
    Private Sub Run()
        Dim threadAlive As Boolean = True
        While threadAlive = True
            RaiseEvent ProcMsg("TestValue") 'Event feuern falls Bedingung 
            ' erfüllt
        End While
    End Sub
End Class

Public Class Form1
 
    Private WithEvents ThreadClass As CThreadGen
    Private Delegate Sub _showMessage(ByVal _msg As String)
 
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As _
      System.EventArgs) Handles MyBase.Load
        ThreadClass = New CThreadGen
        ThreadClass.StartThread()
    End Sub
 
    Private Sub ProcMsg(ByVal _msg As String) Handles ThreadClass.ProcMsg
        If Me.InvokeRequired Then
            Me.Invoke(New _showMessage(AddressOf ProcMsg), New Object() {_msg})
        Else
            Me.txt_output.Text = _msg
        End If
    End Sub
End Class