how create model use variable

[Hariyanto <xhonghar gmail com>]

I create model in treeview like this :

GtkTreeModel *create_model_tw(gint ncol)
{
  GtkListStore *model;

  if (ncol == 2)
    model = gtk_list_store_new (NUM_COLUMNS,   
                              G_TYPE_STRING, 
                              G_TYPE_STRING);

  if (ncol == 3)
    model = gtk_list_store_new (NUM_COLUMNS,  
                              G_TYPE_STRING, 
                              G_TYPE_STRING, 
                              G_TYPE_STRING);
  .
  .
  . until n col

  return GTK_TREE_MODEL (model);
}

GtkTreeModel *fill_model_tw(GtkTreeModel *model, gint ncol)
{
  gint i = 0;
  GtkTreeIter iter;
  
  if (ncol == 2)
    {
      for (i = 0; i < data_tw->>len; i++)
         {
           gtk_list_store_append (GTK_LIST_STORE(model), &iter);
           gtk_list_store_set    (GTK_LIST_STORE(model), &iter,
		  1,
		  g_array_index (data_tw, ColPrefs, i).col1,
		  2,
		  g_array_index (data_tw, ColPrefs, i).col2,
		  -1);
         }
     }
  if (ncol == 3)
     .
     .
     . 
 
  return GTK_TREE_MODEL (model);
}



Is there another way to make it more simple?

thx 
Hariyanto