Dim zahlen As New List(Of Integer)
 
Sub Initialize()
   zahlen.Add(155)
   zahlen.Add(246)
   '...
   ComboBox1.Items.Add("EGC-50-xxxx-TB-KF-GK")
   ComboBox1.Items.Add("EGC-70-xxxx-TB-KF-GK")
End Sub
 
Sub Combobox1_SelectedIndexChanged(...)Handles Combobox1.SelectedIndexChanged
   TextBox1.Text = zahlen(Combobox1.selectedIndex)
End Sub