how to handle a key_press_event when entering GtkComboBoxEntry

["lao wb" <laowenbo gmail com>]

hello, gtk_list
   I'd like to use a GtkComboBoxEntry the same as an URL entry box, need to handle a Enter key pressed event after finishing editing the box.
    
    g_signal_connect((gpointer) comboboxentry1, "key_press_event",
                           G_CALLBACK(on_comboboxentry1_key_press_event), NULL);
    g_signal_connect((gpointer) comboboxentry1, "editing_done",
                           G_CALLBACK(on_comboboxentry1_editing_done), NULL);
   
    I've tried both, neither of them work with me. I've looked up the manual for long, doesn't help, I have to post the question now. Thanks a lot in advance.

Laowb