Question

I am working on a asp.net project having a three-layered implementation. DataAccess Layer is there.DataAccessContract is a layer which contains all the interfaces which classes in dataaccess layer implement.Similarly we have a business layer and a businessLayer contract.

Now when we call Data Access from Business Layer, we call

IUserDAL userControllerDAL=new UserDAL();

UserDAL is inside DataAccess and IUserDAL is inside DataAccessContract.

I could have done it this way

UserDAL user=new UserDAL();

What is the difference between these two approaches and how first one is better than second. is it some pattern in the first case.Please explain with some examples.

Answer 1

See Why are interfaces important

It should answer your question 😀