Hi Joao,

>I get the fowling error in the valid event,
>'No database is open or set as the current database' in the line
> lcPrimaryKey = dbgetprop........ and then
>'variable lcPrimaryKey does not exist'

That means your database isn't open. Do you have a main data base for the application? Is this table apart of the database, and does this table have a primary index? If so, you need to open the database sometime before this happens. I usually open it up at the beginning of my app (OPEN DATABASE is the code) Other wise, use this (this uses the Recno() instead of a primary Key):

local lnCurWA, llReturn, lcExact, leValue, lnRecno()

with This
	lnCurWA = select()
	lcExact = set('exact')
	set exact on
	lnRecno = recno(juststem(.ControlSource))

	use (dbf(juststem(.ControlSource))) again alias EnforceUnique in 0
	select EnforceUnique

	llReturn = !seek(.Value, 'enforceunique', justext(.ControlSource)) or Recno() = lnRecno

	use
	select (lnCurWA)
	set exact &lcExact

endwith
if !llreturn
	MessageB('Value is not unique')
endif
return iif(llReturn, .T., 0)

Does this work?