[Gambas-user] Constant order to process in component creation

[Jorge Carrión]

>Does this help you?

Yes Tobi it's helpfull.

>About your question: If I was you, I wouldn't want to rely on a specific
>order of execution. What if the user sets conexion = Null *mid-execution*?
>You need to handle the case $conexion = Null in your fill_the_grid():

Usually I allways set the code for handling the exceptions of bad use of
users but, since this time the values of properties are set in design time,
I think that shoulden't be necessary control errors in execution time...
But you are right. I must control that user change the value by code (or
lost the database or something like that).

Thank you very much.

Regards


2014-10-02 23:18 GMT+02:00 Tobias Boege <taboege at ...626...>:

> On Thu, 02 Oct 2014, Jorge Carri??n wrote:
> > Excuse my poor English. What I mean with "processing properties" is the
> > execution of triggered methods _read and _write of the propertie.
> > What I mean is  somenthing like that:
> >
> > Export
> >
> > Inherits TableView
> >
> > Public Const _Properties As String = "*,conexion,sqlstring"
> >
> > Property conexion As Connection
> > Property sqlstring As String
> >
> > Private $conexion As Connection
> > Private $sqlstring As String
> >
> > Public Sub fill_the_grid()
> >
> >   $conexion.Exec($sqlstring)
> >   ...
> >   etc.
> >   ....
> >
> > End
> >
> > Public Function conexion_read() As Connection
> >
> >   Return $conexion
> >
> > End
> > Public Sub conexion_Write(Value As Connection)
> >
> >   $conexion = Value
> >
> > End
> >
> > Public Function sqlstring_read() As String
> >
> >    Return $sqlstring
> >
> > End
> > Public Sub sqlstring_write(value As String)
> >
> >    $sqlstring = value
> >    fill_the_grid()
> >
> > End
> >
> >
> > Both properties, conexion and sqlstring, are filled with its values in
> the
> > IDE in design time.
> > When run the program, somtimes the sqlstring_write sub is launched before
> > conexion_write() sub. And then, obviously there are a error in
> > $conexion.Exec($sqlstring) line...
> > Some times If I change the size of the form or if I add som controls more
> > to the form, it works fine.
> >
> > There is a way to force the conexion property to be filled before de
> > sqlstring property?
> >
> > Hope this time I've been more clear.
> >
>
> Yes, it was. (Let me make a quick note on vocabulary here before I proceed:
> you said you programmed a "component" but "component" in the narrower sense
> around Gambas means a sort of shared library (the gb.* things you link to
> your project, like gb.qt4). Your class above _may_ be part of a component
> but you are actually talking about what we normally call a "control", i.e.
> a class which can be put on a graphical form. I know people who call both
> things "component" but this often leads to confusion. And your question
> revolves around that single class, and whether it's part of a component is
> irrelevant here. Remember the 4 C's: classes, controls, components and
> confusion :-))
>
> About your question: If I was you, I wouldn't want to rely on a specific
> order of execution. What if the user sets conexion = Null *mid-execution*?
> You need to handle the case $conexion = Null in your fill_the_grid():
>
> Public Sub fill_the_grid()
>   If Not $conexion Or If Not $conexion.Opened Then Return ' Do nothing
>   $conexion.Exec($sqlstring)
>   ' etc.
> End
>
> Similarly, maybe $sqlstring should get a sensible default value since IIRC
> an empty Exec() also throws an error.
>
> Does this help you?
>
> Regards,
> Tobi
>
> --
> "There's an old saying: Don't change anything... ever!" -- Mr. Monk
>
>
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