I have some set of classes and each of them have some common members,say..

class1

 aID as integer
 aName as string

class2
  bID as integer
  bName as string

class3

   aID as integer
   bID as integer
   cSize as integer
   --------

So what's an ideal solution to design the architecture whether i have to use some interface or abstract class to achieve common properties or something....

Determine what the common members are of each class, and create a super class containing those members. Then derived each subclass from it.

If in your example "aID" and "bID" are actually the same thing, you could place those in the super class. However, in your "class3" you have 2 "..ID" members. That doesn't support the idea that the previous to ".ID" members are the same thing. Perhaps if you explain a bit more about what the specific classes and their members are we can help further. The names you are using are fairly vague.

-Peter

Thanks for your comments .These are my classes

Public Class sport
    Private _sportsId As Integer
    Private _sportsName As String
    Public Property SportsId() As Integer
     -----------
    End Property
    Public Property SportsName() As String
     --------------
    End Property
End Class

========================================

Public Class Equipment
    Private _eqptId As Integer
    Private _eqptName As String
    Public Property EqpmtId() As Integer
        -----------
    End Property
    Public Property EqpmtName() As String
        -----------
End Class
=========================================

Public Class EquipmentFitt
    Private _eqptId As Integer
        Private _sportsId As Integer
        Private _eqpSize As Integer
        Private _eqpFitting As Integer
        Private _sportID As Integer

        Public Property SportsID() As Integer
         -----------
        End Property

        Public Property EquipmentID() As Integer
            ---------
        End Property
        Public Property EquipmentSize() As Integer
         -----------
        End Property
        Public Property EquipmentFitting() As Integer
         -----------
        End Property
             Public Property AthleteID() As Integer
            ---------
        End Property
    End Class

These are business objects just want to hold the data..How the design has to go for getting the common members,I am using vb.net

You might consider object composition where it's appropriate. Here's an example:

Public Class EquipmentFitt

   Private _objSport As sport
   Private _objEquipment As Equipment

   Public Property Sport As sport
      ....
   End Property

   Public Property Equipment As Equipment
      ....
   End Property

   'Add additional internals and properties to further define this EquipmentFitt

End Class

-Peter