For Each ProdField As System.Reflection.FieldInfo In _
      GetType(ProductProperty).GetFields()
 
      Debug.WriteLine(ProdField.Name)
      For Each ProdField1 As System.Reflection.FieldInfo In _
          ProdField.FieldType.GetFields()
 
          Debug.WriteLine("-- " & ProdField1.Name)
 
          'Zum Beispiel (allerdings geht das nicht so einfach 
          'in dieser Schleife, weil Du SubProps deklariert hast.)
          If Prodfield1.Name = .... then 
             ProdField1.SetValue(ProdProp.Prop1, "green")
          End if
      Next ProdField1
Next