An application sends a CB_SELECTSTRING message to search the list of a combo box for an item that begins with the characters in a specified string. If a matching item is found, it is selected and copied to the edit control.
To send this message, call the SendMessage function as follows.
lResult = SendMessage( // returns LRESULT in lResult (HWND) hWndControl, // handle to destination control (UINT) CB_SELECTSTRING, // message ID (WPARAM) wParam, // = (WPARAM) () wParam; (LPARAM) lParam // = (LPARAM) () lParam; );
Specifies the zero-based index of the item preceding the first item to be searched. When the search reaches the bottom of the list, it continues from the top of the list back to the item specified by the wParam parameter. If wParam is –1, the entire list is searched from the beginning.
Pointer to the null-terminated string that contains the characters for which to search. The search is not case sensitive, so this string can contain any combination of uppercase and lowercase letters.
If the string is found, the return value is the index of the selected item. If the search is unsuccessful, the return value is CB_ERR and the current selection is not changed.
A string is selected only if the characters from the starting point match the characters in the prefix string.
If you create the combo box with an owner-drawn style but without the CBS_HASSTRINGS style, what the CB_SELECTSTRING message does depends on whether you use the CBS_SORT style. If the CBS_SORT style is used, the system sends WM_COMPAREITEM messages to the owner of the combo box to determine which item matches the specified string. If you do not use the CBS_SORT style, CB_SELECTSTRING attempts to match the DWORD value against the value of the lParam parameter.