> -----Original Message-----
> From: Geoff Worboys [mailto:geoff@...]
> Sent: Viernes 9 de Marzo de 2001 21:00
>
> In the OnPreparedChanged handler of the dataset initialise the column
> reference according to whether the query is prepared or not (the
> column only exists when the query is prepared)...
>
> if ( MyQuery->Prepared )
> FTmpColumn = MyQuery->FieldByName("MYFIELD");
> else
> FTmpColumn = 0;
>
> Then in the main event handler you can...
>
> if ( FTmpColumn )
> DoSomethingWith( FTmpColumn.AsInteger );

Instead of OnPreparedChanged plus checking Prepared being true, I assume
it's equivalent to write an event handler for AfterPrepare/AfterUnprepare.

C.