AfterOpen corresponds with the cursor being opened, not necessarily the
first record being fetched, or do you mean all records being fetched?

Jason Wharton
CPS - Mesa AZ
http://www.ibobjects.com

----- Original Message -----
From: "Paul Hope" <paulhope@...>
Newsgroups: egroups.ibobjects
To: <IBObjects@yahoogroups.com>
Sent: Thursday, February 28, 2002 3:34 AM
Subject: Re: [IBO] Calculated field column total?


>
> Jason
>
> > Yes, have two calculated fields. One for storage purposes and the other
to
> > hold your real value.
> >
>
> I felt a bit silly after posting the original message because I realised
> that calculated field values are not persistent, they are not stored in
the
> buffer and are only calculated on request (I think). It is therefore not
> possible to access the previous value of a calculated field and therefore
> determine the amount of change. Also if a row is deleted (by a master
> dataset and a refresh) there is no event to allow the row value to be
> removed from the total.
>
> I think the only option is to sum the whole buffer after each refresh. It
> would be neater if there was an event to hang the calculation on rather
than
> having to call it in code after any refresh or open call.
>
> This is one of the differences I found between IBO and the BDE. In the
BDE
> AfterOpen meant 'after the data is retrieved and you can now process it' -
I
> don't think IBO works the same way (unless some flags cause it to) and the
> only way to get equivalent functionality is to code the after open stuff
> after the call to Open/refresh etc. I would have thought an
> AfterGettingTheData event would be very useful (please tell me if it
already
> exists and I've missed it :-))
>
> Regards
> Paul
>
>
>
>
>
> > Jason Wharton
> > CPS - Mesa AZ
> > http://www.ibobjects.com
> >
> >
> > ----- Original Message -----
> > From: "Paul Hope" <paulhope@...>
> > Newsgroups: egroups.ibobjects
> > To: <IBObjects@yahoogroups.com>
> > Sent: Wednesday, February 27, 2002 4:45 AM
> > Subject: [IBO] Calculated field column total?
> >
> >
> > > Hi
> > >
> > > I want to display a total of a calculated field for a read only
dataset
> > > displayed in a grid. I could fire off another query on the server
> asking
> > it
> > > to recalculate a total every time a row changes in the displayed
> dataset -
> > > but this seems very inefficient.
> > >
> > > What I was hoping to do is in CalculateField
> > > subtract ARow.ByName('MyCalculatedField').asCurrency from my total
> > > calculate the new value of MyCalculatedField
> > > add the new value to my total
> > >
> > > Unfortunately reading the calculated field value before it is set
> doesn't
> > > work. It seems to return the value it had calculated for the previous
> > row.
> > >
> > > I have also tried summing the field values in the buffer (having set
> > > Fetchall to true) but I havn't found an appropriate event to attach
this
> > > to - 'AfterRefresh' would be nice.
> > >
> > > Any Ideas?
> > >
> > > Regards
> > > Paul