Form viewers call the IMAPIFormMgr::SelectForm method to first present a dialog box that enables the user to select a form and then to retrieve a form information object that describes the selected form. The dialog box constrains the user to select a single form.
The SelectForm dialog box displays only forms that are not hidden (that is, forms that have their hidden properties clear). If a form viewer passes the MAPI_UNICODE flag in the ulFlags parameter, all strings are Unicode. Form library providers that do not support Unicode strings should return MAPI_E_BAD_CHARWIDTH if MAPI_UNICODE is passed.