Combo-box messages are sent by an application to a combo box. The following list briefly describes each combo-box message:
| Message | Description | |
| CB_ADDSTRING | Adds a string to the list box of a combo box. | |
| CB_DELETESTRING | Deletes a string from the list box of a combo box. | |
| CB_DIR | Adds a list of the files from the current directory to the combo box. | |
| CB_FINDSTRING | Finds the first string in the combo-box list box which matches a prefix. | |
| Message | Description | |
| CB_GETCOUNT | Returns a count of the number of items in the combo box. | |
| CB_GETCURSEL | Returns the index of the currently selected item, if any. | |
| CB_GETEDITSEL | Returns the starting and ending positions of the selected text in the edit control of a combo box. | |
| CB_GETITEMDATA | Retrieves a 32-bit value associated with an item in an owner-draw combo box. | |
| CB_GETLBTEXT | Copies a string from the list box of a combo box into a buffer. | |
| CB_GETLBTEXTLEN | Returns the length of a string in the list box of a combo box. | |
| CB_INSERTSTRING | Inserts a string in the combo box. | |
| CB_LIMITTEXT | Limits the length of the text that the user may enter into the edit control of a combo box. | |
| CB_RESETCONTENT | Removes all strings from a combo box and frees any memory allocated for those strings. | |
| CB_SELECTSTRING | Changes the current selection to the first string that has the specified prefix. The text in the edit control is changed to reflect the new selection. | |
| CB_SETCURSEL | Selects a string and scrolls it into view, if necessary. | |
| CB_SETEDITSEL | Selects all characters in the edit control that are within specified starting and ending positions. | |
| CB_SETITEMDATA | Sets a 32-bit value associated with an item in an owner-draw combo box. | |
| CB_SHOWDROPDOWN | Shows or hides a drop-down list box in a combo box. |