An application sends the CB_SETDROPPEDWIDTH message to set the maximum allowable width, in pixels, of the list box of a combo box with the CBS_DROPDOWN or CBS_DROPDOWNLIST style.
CB_SETDROPPEDWIDTH
wParam = (WPARAM) wWidth, // width of list box, in pixels
lParam = 0, // not used, must be zero
Parameters
wWidth
Specifies the width of the list box, in pixels.
Return Values
If the message is successful, The return value is the new width of the list box.
If the message fails, the return value is CB_ERR.
Remarks
By default, the minimum allowable width of the drop-zdown list box is 0. The width of the list box is either the minimum allowable width or the combo box width, whichever is larger.
See Also