For example, if you have grid.textbox with character controlsource:
Textbox.Gotfocus event

This.Tag=This.Value

Textbox.Lostfocus event

If Alltrim(This.Value)==Alltrim(This.Tag)
  Return
Endif
*** validation code here

>Ed
>What kind of trigger, my brain cells aren't focusing.
>
>>>Naomi
>>>In the Valid or LostFocus the first statement is to verify that a close or cancel button has not been clicked.
>>>

>>>LOCAL oLoc,lsValue,llAct,llOK,lsMsg
>>>STORE "" TO lsValue,lsMsg
>>>STORE .T. TO llAct,llOK
>>>* get the location of the Cancel & Close button (cmdDelete & cmdClose) 
>>>* get reference to object under mouse pointer
>>>oLoc = sys(1270)
>>>if vartype(oLoc)="L"
>>>	oLoc = This
>>>endif
>>>IF !INLIST(lower(oLoc.name),"cmdUpdate","cmddelete","cmdedit","cmdadd","cmdclose")
>>>

>>>
>>>I believe it "finally" dawned on me that there was an issue with that code. if the mouse pointer is left on the add or edit button after either are clicked, the Valid or LostFocus code does not run, "by design"...crap! I have had issues like this (valid code not running), intermittently for a while. Who knows why the light-bulb just turned on! It helps to have the coverage profiler turned on.
>>>
>>>When I removed the above reference to "cmdedit, cmdadd" the code works.
>>>
>>>Is there a better way to keep the valid from running when closing the form or canceling a process?
>>>
>>If you use LostFocus then simple trigger will ensure that code will fire just in case textbox.value has been changed by user; at this point, if needed, you may still disallow to close the form.