Re: Forms inheritance best practice

From: Jonathan Allen (x_at_x.x)
Date: 09/27/04 

Date: Mon, 27 Sep 2004 16:45:13 -0700

That really depends on the nature of your base class. I only use form
inheritance for visual features like a toolbar or menu that has to be on
every form. 

-- 
Jonathan Allen
"Daniel Billingsley" <dbillingsley@NO_durcon_SPAAMM.com> wrote in message
news:%23doLnjMpEHA.3712@TK2MSFTNGP15.phx.gbl...
> My application will have various forms for editing my business objects.
All
> the objects to be edited on the various forms will either derive from a
> common class or implement a common interface.  Let's just say it's an
> interface for sake of this discussion.
>
> There is a lot of common functionality between the forms, of course.
Using
> forms inheritance seemed like a great way to reuse that common code.
>
> Of course there are some parts of the common code that need to interact
with
> the interface, but the actual business object appropriate for the
particular
> derived form will of course be instantiated by the derived form.  The
> controls specific to editing that type of business object will of course
be
> on the derived form.
>
> So, it seemed logical to create some abstract methods and properties in
the
> base form.  That means the class itself must be abstract.  Not so fast -
the
> designer complains it needs to instantiate the base class and can't
because
> it's abstract.
>
> Hmmm..
>
> That leaves me with two options that I can see.  I'm just wondering which
is
> considered a better practice, or if there's a third I haven't thought of.
>
> 1)  Declare protected fields (of the interface Type) in the base form
which
> could be set directly in the derived form in all the appropriate places.
>
> 2)  Declare the needed methods and properties as virtual in the base
class.
> In the base class each simply throws a NotSupportedException since only
the
> override in the derived form should actually be used.
>
>

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