error lnk2001: unresolved external symbol

protected:
    //{{afx_msg（cserverview)
    //}}afx_msg
    afx_msg  lresult onthreadmsgsend（wparam wparam, lparam lparam);
        declare_message_map（)

begin_message_map（cdmserverview, cformview)
//{{afx_msg_map（cserverview)
    //}}afx_msg_map
// standard printing commands
on_command（id_file_print, cformview::onfileprint)
on_command（id_file_print_direct, cformview::onfileprint)
on_command（id_file_print_preview, cformview::onfileprintpreview)
on_message（wm_thread_message_send,cserverview::onthreadmsgsend)
end_message_map（)

lresult cserverview::onthreadmsgsend（wparam wparam, lparam lparam)
{
    return 0;
}