Why not? Just return 0 to suppress VFP standard message.
You can also use LostFocus and set NODEFAULT in achieve the same.

>These codes are on text1.valid event
>

>IF m.getvalue=0
>MESSAGEBOX('Rate Not Found'+CHR(13)+'Please check rate','Accounting System')
>return.f.
>endif
>

>For some reasons I do not want to use above codes on Valid event,
>How to use some other event, if m.getvalue=0 then control must reamains in text1.
>