[Lazarus] Is it meaningful or possible to change the visibility or the properties and events in a form or datamodule, ie make the private or protected?

[Frank Church]

On 23 March 2012 14:15,  <michael.vancanneyt at wisa.be> wrote:
>
>
> On Fri, 23 Mar 2012, Michael Fuchs wrote:
>
>> Am 23.03.2012 14:55, schrieb Frank Church:
>>>
>>> [...]  I'd prefer to look only at the public section and say, Oh,
>>> this is what it does for the program's other modules. Whatever isn't
>>> there is not relevant to the rest of the application.
>>>
>>> I understand that it comes from a Delphi legacy as RAD tool dating
>>> from a time when the principles underlying object orientation had not
>>> properly sunk in. [...]
>>
>>
>> You can already do this by changing the way you are programming. Just
>> write a class which only publish the needed methods and properties to the
>> outside.
>> Don't let the Application create and control your forms, move this to your
>> class. So, your class hides the forms, datampdules and other stuff.
>
>
> That's what I do too.
>
> unit appforms;
>
> type
>  TBaseMyForm = Class(TForm)
>    // Define public interface
>  end;
>  TBaseMyFormClass = Class of TBaseMyForm;
>
> Var
>  MyFormClass : TBaseMyFormClass = Nil
>
> And then somewhere:
>
>
>
> Type
>  TForm = TBaseMyForm;
>
>  TMyForm = Class(TForm);
>   // Regular lazarus definition of form
>  end;
>
> initialization
>  MyFormClass = TMyForm; end;
>
> And then, whenever I need an instance of TBaseMyForm:
>
> F:=MyFormClass.Create(Self);
>
> You could even substitute the complete TMyForm form with another one,
> depending on
> configuration options.
>
> Michael.
>

Will I be able to develop TMyForm in the Object Inspector as usual,
although TForm has been redefined as a class of TMyForm? Will the unit
in which TMyForm defined still use the Forms unit, or will that be
inherited from the inclusion of the unit appforms (in your example)?

Is there some place in the Free Pascal or Object Pascal docs that the
principles are explained?


>
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-- 
Frank Church

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