The following notification codes apply to combo boxes:
| Message | Description | |
| CBN_DBLCLK | Sent when the user double-clicks a string with the mouse. | |
| CBN_DROPDOWN | Informs the owner of the combo box that its list box is about to be dropped down. | |
| CBN_EDITCHANGE | Indicates that the user has altered text in the edit control. | |
| CBN_EDITUPDATE | Indicates that the edit control will display altered text. | |
| CBN_ERRSPACE | Sent when the system is out of memory. | |
| CBN_KILLFOCUS | Indicates that a combo box has lost input focus. | |
| CBN_SELCHANGE | Sent when the selection has been changed. | |
| CBN_SETFOCUS | Indicates that the combo box has received input focus. |