[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.
>
>
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Hi Michael, could you help me clarify how the units are linked.

>From reading your code I get the impression that I create TMyForm
separately then copy all of its code into appforms.pas. It is not a
matter of adding the unit or TMyForm in appforms? Or is the other way
round in which the unit of myform.pas has appforms included in its
units?

The first option also implies that I must include the .lfm file of
myform in appforms.

So in a nutshell does it mean I create TMyForm in the usual manner,
using the IDE then copy all its contents into appform, then add  TForm
= TBaseMyForm to the top of its type definition?

I know I've got to brush up on my Object Pascal concepts, but some
help here would be really welcome
-- 
Frank Church

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