DWORD GetEditSel() const;
Gets the starting and ending character positions of the current selection in the edit control of a combo box.
A 32-bit value that contains the starting position in the low-order word and the position of the first nonselected character after the end of the selection in the high-order word. If this is used on a combo box without an edit control, CB_ERR is returned.
CComboBox::SetEditSel, CB_GETEDITSEL