int GetLBTextLen( int nIndex ) const;
nIndex
Contains the zero-based index of the list-box string.
Gets the length of a string in the list box of a combo box.
The length of the string in bytes, excluding the terminating null character. If nIndex does not specify a valid index, the return value is CB_ERR.
CComboBox::GetLBText, CB_GETLBTEXTLEN