GtkCombo::set_item_string
void set_item_string(
      GtkItem item
     , string item_value); 
    
     As you may have noticed in the GtkCombo 
     constructor example, it is not by any means essential that the 
     items in a GtkList are 
     GtkListItems.  This method is intended to
     provide a way to give an alternative to the entry box, where only
     the string data type is allowed.
    
    
     set_item_string()  can be set
     regardless of whether there is already text in the list item, and
     in either case will provide the string that is compared against the
     entry's text content during search routines.
    
    
      This method determines the string that will be displayed in the
      entry field after the list item has been selected.