>I have tried tracing the methods but everthing seem fine
>
>this the code where the problem arises which is from tastrade grid class which I have used with only one minor change for evaluating the order for calculation.
>******************
>IF EMPTY(this.cFieldToSum)
> RETURN
>ENDIF
>
>LOCAL lnOldArea, ;
> lnOldRecNo, ;
> luKey, ;
> lcFieldToSum, ;
> lcOrder,;
> lstalk
>
>
>lnOldArea = SELECT()
>this.nColumnSum = 0
>lcFieldToSum = ""
>
>IF EMPTY(this.RecordSource)
> RETURN
>ENDIF
>
>*-- Select the alias specified in the grid's RecordSource property
>SELECT (this.RecordSource)
>
>lcOrder = ORDER()
>luKey = IIF(!EMPTY(lcOrder), EVAL(key(tagno())), "")
>lnOldRecNo = IIF(EOF(), 0, RECNO())
>lcFieldToSum = this.cFieldToSum
>
>lstalk = set('talk')
>set talk off
>*-- Total up the column and store the result
>*-- in the nColumnSum property
>IF !EMPTY(lcOrder) AND SEEK(luKey)
> SUM &lcFieldToSum. ;
> WHILE luKey = EVAL(key(tagno())) ;
> TO this.nColumnSum
>ELSE
> IF CURSORGETPROP("SOURCETYPE") = DB_SRCLOCALVIEW OR ;
> CURSORGETPROP("SOURCETYPE") = DB_SRCREMOTEVIEW
> *-- Grid is bound to a view
> SUM &lcFieldToSum. ;
> TO this.nColumnSum
> ENDIF
>ENDIF
>
>IF lnOldRecNo <> 0
> GO lnOldRecNo **********Error Occurs Here**********
>ENDIF
>
>SELECT (lnOldArea)
>if lstalk = 'ON'
> set talk on
>endif
>***********
>
>Rajesh

---

Rajesh,
You say it's optimistic buffering (and as far as I remember it's a must for wizard generated forms) but you don't say if it's a row or table buffering. My gut guess you're using row buffering. Say you have 100 records and add a new one which gets recno -1. As this method runs, "sum" moves the record pointer and an implicit tableupdate() occurs causing your "current row" to be 101 (in a multiuser environment might be higher). You store -1 to lnRecno which no longer exists after "sum". As a workaround either change your buffering to table or store a unique field value (ie: I also use PK like field for childs even if they're not used to link to some other table) that you can seek after sum.

OTOH I would never use a code something like this that moves the record pointer out of my will and unnecessarily does summing many times (if your child records count for a particular parent key increases users would start to wait more and more to get cursor back ). Instead sum once as parent changes using SQL, in field's valid or lostfocus add just the "difference" of old value and value to already summed value.
Cetin