[Lazarus] Master-detail-subdetail

[patspiper]

On 01/04/2011 05:18 PM, michael.vancanneyt at wisa.be wrote:
>
>
> On Tue, 4 Jan 2011, Koenraad Lelong wrote:
>
>> Hi,
>>
>> I have a database (firebird) with master-data, detail-data and
>> sub-detail-data.
>> In lazarus 0.9.28.2, svn 22279, I defined a TIBConnection, a
>> TSQLTransaction and three TSQLQuery's. The detail has as its datasource
>> a datasource coupled with the master. The subdetail has as its
>> datasource a datasource coupled with the detail.
>> To show the data I have three TDBGrids, their datasources are those
>> three datasources coupled with the three queries.
>>
>> When I start the application, the master that shows has several details,
>> each having several sub-details. When I scroll the details, the
>> subdetails follow the detail. That's good. But when I scroll the master,
>> only the details follow, the subdetail-grid goes blank.
>>
>> To try finding what happens I added a button that opens the
>> sub-detail-query. If I click on it I get the expected subdetails. When I
>> scroll the master again, the subdetail disappears again. Again I can get
>> it back by clicking my debug-button.
>>
>> To debug this further, I added events for beforescroll, afterscroll,
>> beforeclose and beforeopen for all three queries which write to a
>> logfile. It seems that the beforeclose event is not fired for the
>> subdetail-query, although it is closed somehow.
>>
>> I hope this makes sense to someone. Is there anything I'm missing ? Or
>> have I found a bug ?
>
> There is no principle difference between the master/detail and the
> detail/subdetail relation, so I'd expect your setup to work.
>
> Can you check whether the AfterScroll events occur for 
> master/detail/subdetail ?
>
> Michael.
That's a bug I had encountered a very long time ago.

Stephano