Private Sub Button_Test_Click(ByVal sender As Object, ByVal e As _
  System.EventArgs) Handles Button_Test.Click 
    Me.BeginInvoke(New Threading.ThreadStart(AddressOf StartTestThread)) 
End Sub 
 
Private Sub StartTestThread() 
    Klasse.Methode(DataGridView_Test) 
End Sub

Public Sub SearchFlights(ByRef pDataGridView As DataGridView) 
   Result = fServiceObject.Test(fTestObject)
   'Trage ergebnis ins übergebene DataGridView ein
End Sub