We have seen at many places we are preferred to use Custom entity classes over Dataset, I came across some useful articles which has reason behind this, and sample code for Base entity and entity collection classes (including non-generic as well as generic(.Net 2.0) version).

On the Way to Mastering ASP.NET: Introducing Custom Entity Classes
http://msdn2.microsoft.com/En-US/library/aa479317.aspx

In brief

Problem with DataSet

- Lack of Abstraction

o The first and most obvious reason to consider alternatives is the DataSet’s inability to decouple your code from the database structure.

- Weakly-Typed

o DataSets are weakly-typed, which makes them error prone and likely to impact your development effort.

- Not Object-Oriented

o DataSets are objects and C# and Visual Basic .NET are object-oriented (OO) languages doesn’t automatically make your usage of them object-oriented. The “hello world” of OO programming is typically a Person class that is sub-classed by an Employee class. DataSets, however, don’t make this type of inheritance, or most other OO techniques, possible (or at least natural/intuitive).

Benefit with Custom Entity Classes

- Take advantage of OO techniques such as inheritance and encapsulation

- You can add custom behavior

- Object-Relational Mapping

- Mapping Custom Collections

- Managing Relationships between two entities in Object oriented way