Re: [DUG]: Passing DataSet to Quick Report

[Mark Howard]

James Never apologise for providing assistance - it's always useful!   Nello   Your comments have given me cause to revisit my basic design - and as usual, you have hit the nail on the head.  My problems stem from an earlier lack of understanding of how Delphi works and I had (un-necessarily) created several TQuery's (each of which I was trying to pass to the report) when one would have done.  (I can see the eyes rolling!).   Have now fixed it.    Thanks everyone for your help.   Mark ----- Original Message ----- From: James Low To: Multiple recipients of list delphi Sent: Wednesday, May 02, 2001 3:20 PM Subject: RE: [DUG]: Passing DataSet to Quick Report ...and reading the original enquiry! Sorry Mark. -----Original Message----- From: Nello Sestini [mailto:[EMAIL PROTECTED]] Sent: 2 May 2001 18:40 To: Multiple recipients of list delphi Subject: Re: [DUG]: Passing DataSet to Quick Report   Maybe this is one case where setting a global variable IS appropriate?!   FWIW i think having the dataset "outside"  sort of violates the principle James argued earlier that everything should be visible within the report unit.    Because otherwise the function of the report is dependant on "stuff you can't see" like the details of the query and field definitions of the outside dataset.   But if you insist on doing that - there are some ways to pass the thing in.   You don't have to resort to globals the way a VB programmer probably would   You can:   1.  Make the dataset a property of the form containing     the quickreport component and set that property     after you create the form but before you show it.   2.  Make the dataset a parameter of the constructor     of the form and have the constructor use it to set     things up when you create the form (or at least     save it in a private field)   3.  If the form is modeless and you want to be able     to change the dataset without destroying/recreating     the form you can add a method to the form     and include the dataset as a parameter to the method.   4.  you can include a procedure in the same unit as the     form containing the quickreport (but not a method     of that form) that creates an instance of the form     and accepts the dataset as a parameter.    Since     it's in the same unit, it will have access to all     the forms private fields just as a method would     and could set a private field (much as a constructor     would)   5.  If you won't be invoking the QR from lots of different     places, consider putting the QR component on the     SAME FORM as the unit that will invoke it - but "off camera"     (i.e. beyond the borders of the window so it doesn't     display).    This won't inhibit the "preview" function     at all - it will still show.   And it eliminates     the need to "pass" a lot of information between     forms when you generate the report.   I'd probably favour 1 or 5 - but not sure there's a compelling case to be made for preferring any one of these over another.   -ns