[Gambas-user] Forward events from constructor

[Benoît Minisini]

Le 04/10/2015 18:43, Tobias Boege a écrit :
> On Sun, 04 Oct 2015, Beno??t Minisini wrote:
>> Le 04/10/2015 18:29, Tobias Boege a ?crit :
>>> On Sat, 03 Oct 2015, Beno??t Minisini wrote:
>>>>> Is there a limitation, about raising events from constructors, I don't know
>>>>> of? Also note how, in the demonstration project, I can very well initiate
>>>>> the validation procedure just after the constructor finished.
>>>>>
>>>>
>>>> The logic behind that behaviour is that an object whose constructor is
>>>> not finished should not be able to raise or catch events.
>>>>
>>>> Said differently, an object must be ready to deal with events.
>>>>
>>>
>>> Uff, I didn't expect the answer to make this much sense...
>>>
>>
>> It's not technically necessary to do that, but it avoids a lot of
>> possible annoying bugs in your code.
>>
>
> I understand. And by the way, that Timer trick works even in the following
> form:
>
> --8<--[ ValidateBox.class]--------------------------------------------------
>    Private $frmControl As FValidateBox
>    Private $hTimer As Timer
>
>    Public Sub _new()
>      $frmControl = New FValidateBox(Me) As "Control"
>
>      $hTimer = New Timer As "FirstCheck"
>      $hTimer.Delay = 1
>      $hTimer.Start()
>    End
>
>    Public Sub FirstCheck_Timer()
>      $hTimer.Stop()
>      $frmControl.txtInput_Change() ' Trigger first validation
>    End
> --8<------------------------------------------------------------------------
>
> The 1 millisecond timer delay is provocative enough that everyone who reads
> the code will get that this is a hack and why it's there for. It is not as
> self-explanatory as the GB.Post() API which we have in C, though.
>
> Regards,
> Tobi
>

You should not do that (put an arbitrary delay), but instead use the 
Timer.Trigger() method, which will raise the Timer event at the next 
event loop.

Regards,

-- 
Benoît Minisini