[Lazarus] Exception dialog

[Martin Friebe]

Luca Olivetti wrote:
> En/na Hans-Peter Diettrich ha escrit:
>
>   
>> Insert your exception handler in an more appropriate place, depending on 
>> the concrete application. The user can expect a diagnosis of what went 
>> wrong, and a chance for correcting his preceding input.
>>     
>
> For data aware components (and probably for others too), 
> Application.OnException is the only place, otherwise you cannot trap 
> exception that are no caused by your program flow but by intrinsic 
> processing by the component (e.g. during post the database could reject 
> the data due to failed constraints, you could trap BeforePost or 
> AfterPost but not DuringPost).
>   
If a component throws an exception outside any call  from your code 
(which you can place in a "try except end"), a place like OnDataReceived 
which is triggered automatically, then this component has a bug (IMHO).
The component *should* have something like an OnError event on which it 
can call your code. Or it should have a flag/state, on which it said 
that an error occurred.
An Exception may be, if an OnError event is provided, but not assigned.

Best Regards
Martin