[Lazarus] Exception dialog

[Martin Friebe]

Graeme Geldenhuys wrote:
> Please note, I don't use db-aware components, but here follows the
> help from Kylix 3.
>
> On Tue, Mar 17, 2009 at 3:46 PM, Martin Friebe <lazarus at mfriebe.de> wrote:
>   
>> I have to admit, I have limited knowledge of the exact details of the
>> data-aware components, and rather was making a general case about my
>> perception of proper exception use.
>> I just googled  => can you point me to some documentation on it?
>>
>> Following you description, I have no problem if an OnValidate allows the
>> code to use an exception to signal the component some-error state.
>> IMHO the component should have a well defined behaviour on getting this
>> exception.
>>     
>
>
> ==========[ Kylix 3 help ]================
> OnValidate event (TField)
> -------------------------
> Occurs just before the data is written to the record buffer.
>   
.....
> To reject the current value of the field from the OnValidate event
> handler, raise an exception.
>
>   
Then to me the Delphi/Kylix implementation is flawed. Because it forces 
me to do TWO things, even if I want to do only one of them.
There should be:
- an ExceptionClass TDataValitaionException (or whatever) which can be 
used to abort writing the data, but not defer error handling to the mainloop
- any other exception, that aborts the write, and transfers error 
handling to the main loop

There are usages for both scenarios, so they should both be possible.

Best Regards
Martin