Abstraction question

**Joseph Bittman MVP MCSD** · Sep 6 '06, 07:55 PM

Re: Abstraction question

Sept. 6, 2006

I don't quite understand the question completely, but if you are wanting
your code to work and explain why the error is occuring.... it may be
because you have declared a variable "_person" which is the exact same name
as the MustInherit class _Person (I don't believe class names & variables
are case-insensitive in C#... like if you have Button1 object on your
windows form, you can't declare "button1" in your code.)

So anyway, try changing your _person variable to something else like
"persontoreturn " or something.

Hope this helps and is what you were asking for!
--
Joseph Bittman
Microsoft Certified Solution Developer
Microsoft Most Valuable Professional -- DPM

Web Site/Blog: http://CactiDevelopers.ResDev.Net/

"Eric Cathell" <depictureboy@c ommunity.nospam wrote in message
news:ed%23ysSc0 GHA.4580@TK2MSF TNGP05.phx.gbl. ..

>I am using dOOdads as my persistence layer.
>
I have a business object Person that sits in a Project called DOMAIN
I have 2 dOOdads in a project called BLL.
>
one is _Person and is declared MustInherit
the other is Person and is my concrete class.
>
My main goal of BLL.Person is to protect custom methods and properties
against regeneration.
>
DOMAIN.Person is my actual object for all my Rules and such for person.
>
so in DOMAIN.Person I have code like this
>
Private _person As BLL.Person
>
Public Function getPersonByID(B yVal id As Integer) As BLL.Person
>
If _person.LoadByP rimaryKey(id) = False Then
Throw New Person.InvalidP ersonException
End If
Return _person
>
End Function
>
The problem is I am getting the following error in my compiler:
Construct makes an indirect reference to project 'WavelengthIS.C MR.BLL',
which contains 'WavelengthIS.C MR.BLL.Person'. Add a project reference to
'WavelengthIS.C MR.BLL' to your project. C:\Documents and
Settings\ecathe ll\My Documents\Visua l Studio
2005\Projects\W avelengthIS\CMR-Versioned\Nunit TESTS\Form1.Des igner.vb
>
Now I am sure there is some design way around this. I am just delving into
some of the more complex patterns and the thought is at the tip of my
brain. I am missing an interface somewhere( probably in my function) as
IPerson.
>
but if I do an interface on IPerson...how do I maintain the bll._person to
bll.Person inheritence?
>
Hopefully what I am asking makes some kind of sense.
>

**Eric Cathell** · Sep 7 '06, 08:35 PM

Re: Abstraction question

I got that issue solved but lets carry on with this conversation. I think I
am confused about abstraction.

we have a class

Namespace myCompany.MyPro gram.DAL
Protected MustInherit Class _Person

members
properties
methods

end Class
end Namespace

Now This class is kept in a separate project so that DAL will compile into
its own DLL.

next we have this

imports myCompany.MyPro gram.DAL

Namespace myCompany.MyPro gram.BLL
Public Class Person
Inherits _Person

members
properties
methods

end Class
end Namespace

Once again this is kept in a separate project so that BLL will compile into
its own DLL.

Now if I want to create a facade layer(because person has several dependent
objects that the end user really doesnt need to know about.

So now I have

Namespace myCompany.MyPro gram.Domain
Public class PersonFacade

private _p as Person

public sub new()
_p=new Person
end sub
public sub SimplePersonMet hodAccessor
_p.DoSomething

End Class
End NameSpace

Now my PersonFacade must have a reference to BLL *AND* DLL otherwise the
properties and such in DLL wont be visible. (maybe my visibility is wrong)
How is this abstracting? I understand why the reference is needed to
BLL...but why DLL too? Shouldn't DLL be totally insulated from knowledge?

It seems a lot of the patterns I have been looking over work logically
well...until you throw in a datastore. Then the reasons for decorators or
bridges or strategy patterns disappear...

I have been looking into NHibernate..but I am working on a large project so
I am using dOOdads instead. But I want a good level of abstraction between
my web interface and my BLL thus the facade...But if I ever had to change
the backend implementation or the datalayer changed for some reason I need
to know that I am abstracted enough from the interface.

I have read Headfirst Design patterns. I have the Wrox Professional design
patterns book. But like I said none of them really tackle patterns from the
point of having a persistence layer. A lot of the reason for the some of the
patterns are invalidated(in my mind) when you have a datastore.

"Joseph Bittman MVP MCSD" <RyanBittman@ms n.comwrote in message
news:%23B$7a7e0 GHA.1268@TK2MSF TNGP02.phx.gbl. ..

Sept. 6, 2006
>
I don't quite understand the question completely, but if you are wanting
your code to work and explain why the error is occuring.... it may be
because you have declared a variable "_person" which is the exact same
name as the MustInherit class _Person (I don't believe class names &
variables are case-insensitive in C#... like if you have Button1 object
on your windows form, you can't declare "button1" in your code.)
>
So anyway, try changing your _person variable to something else like
"persontoreturn " or something.
>
Hope this helps and is what you were asking for!
--
Joseph Bittman
Microsoft Certified Solution Developer
Microsoft Most Valuable Professional -- DPM
>
Web Site/Blog: http://CactiDevelopers.ResDev.Net/
>
"Eric Cathell" <depictureboy@c ommunity.nospam wrote in message
news:ed%23ysSc0 GHA.4580@TK2MSF TNGP05.phx.gbl. ..

>>I am using dOOdads as my persistence layer.
>>
>I have a business object Person that sits in a Project called DOMAIN
>I have 2 dOOdads in a project called BLL.
>>
>one is _Person and is declared MustInherit
>the other is Person and is my concrete class.
>>
>My main goal of BLL.Person is to protect custom methods and properties
>against regeneration.
>>
>DOMAIN.Perso n is my actual object for all my Rules and such for person.
>>
>so in DOMAIN.Person I have code like this
>>
> Private _person As BLL.Person
>>
> Public Function getPersonByID(B yVal id As Integer) As BLL.Person
>>
> If _person.LoadByP rimaryKey(id) = False Then
> Throw New Person.InvalidP ersonException
> End If
> Return _person
>>
> End Function
>>
>The problem is I am getting the following error in my compiler:
>Construct makes an indirect reference to project 'WavelengthIS.C MR.BLL',
>which contains 'WavelengthIS.C MR.BLL.Person'. Add a project reference to
>'WavelengthIS. CMR.BLL' to your project. C:\Documents and
>Settings\ecath ell\My Documents\Visua l Studio
>2005\Projects\ WavelengthIS\CM R-Versioned\Nunit TESTS\Form1.Des igner.vb
>>
>Now I am sure there is some design way around this. I am just delving
>into some of the more complex patterns and the thought is at the tip of
>my brain. I am missing an interface somewhere( probably in my function)
>as IPerson.
>>
>but if I do an interface on IPerson...how do I maintain the bll._person
>to bll.Person inheritence?
>>
>Hopefully what I am asking makes some kind of sense.
>>

>
>

Abstraction question

Abstraction question

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