CODEWITHSUNDEEP
asp.netvb.net.net-3.5abstract-class3-tier
dotnetN00b
dotnetN00b

Reputation: 5131

How do I use abstract classes in a 3-tier solution?

My immediate issue is that currently I have a 3 tier solution (Presentation.aspx.vb calls BusinessLayer.vb which calls DataAccessLayer.vb). However, I want to make BusinessLayer and DataAccessLayer.vb abstract classes because several Webforms will use have the same functionality.

So I currently am doing this (no abstract classes):

'Presentation Layer (pseudocode)

public sub checkUser(byval userName as string, byval dept as string)

   dim isGood as boolean = BL.checkUserAccess(userName, dept)

   'some more code
   'change properties of webcontrols, etc

end sub



'Business Layer (pseudocode)

public function checkUserAccess(byval name as string, byval group as string) as boolean

   dim accessObject as dataObject =  DAL.checkPermissions(name, group)

   if accessObject.isHighAccess then
      'some code
   else
      'some other code      
   end if 

end function



'Data Access Layer (pseudocode)

public function checkPermissions(byval userid as string, byval section as string) as dataObject

   'some code

end function

However can I still have this structure if I add abstract classes?

For instance:

'Presentation Layer (pseudocode)

public sub checkUser(byval userName as string, byval dept as string)

   dim isGood as boolean = instOne_BL.checkUserAccess(userName, dept)

   'some more code
   'change properties of webcontrols, etc

end sub



'Business Layer (pseudocode)

public class instOne_BL inhertis BL

   public function checkUserAccess(byval name as string, byval group as string) as boolean

      base.checkUserAccess(name, group)
      instOne_DAL.checkPermissions(name, group)

   end function
end class      


'Data Access Layer (pseudocode)

public class instOne_DAL inherits DAL

   public function checkPermissions(byval userid as string, byval section as string) as dataObject

      base.checkPermissions(userid, section)

   end function
end class

Upvotes: 0

Views: 797

Answers (1)

competent_tech
competent_tech

Reputation: 44941

If you use .Net remoting as the communication layer between the layers, then this is no problem at all (it's just like calling a method in another class within the current layer).

If you use WCF, then this will also work, buy you need to do a little more work. The base/abstract class must be decorated with KnownType attributes of all inheriting classes that you expect to pass.

If you use web services, then this is not possible without playing some games. For example, you would need to serialize the object into a string using the binary serializer and then deserialize it on the other end.

Upvotes: 1

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