Purpose of Interface

Question

Hi What is use of Interface?Is there any situation that I cannot avoid interfaces? Regards Kishore Kumar

Vulpes · Answer

Off the top of my head the only situations I can think of where you have to implement interfaces is where you want your classes to be enumerable using foreach or Linq to be sortable using the various .NET Framework Sort methods or to be bindable as a data source for various controls. Your classes would then need to implement the .NET Framework interfaces : IEnumerator/IEnumerable IComparer/IComparable IList/IBindingList or their generic equivalents.

kishore kumar · Answer

Hi Vulpes Thanks for the reply. I feel interface just adds an extra layer to the solution and it does not provide any implementation. Consider there are two scenarios 1.Create a classwhich inherits an interface and implements its methods 2.Create a class and write your own methods without using interfaces In the second scenario we are not using any interfaces and still we could acheive the same task.My question isis there any similar situation exists where I cannot work without interfaces

Maha · Answer

CREATING AND USING INTERFACES

Vulpes · Answer

The purpose of interfaces is to enable classes or structs which are otherwise unrelated to one another to share functionality. Each class/struct can implement the interface's members in a way which suits it but it must provide a public implementation of all of them. It's possible to create variables and parameters of interface types to which you can assign references to objects which implement the interface in question. This enables you to write generic code in relation to all types which implement an interface. It's also possible for types to implement multiple interfaces which can compensate to some extent for .NET's lack of support for multiple inheritance. If you write programs of any size it's going to be difficult to avoid interfaces as the .NET Framework makes extensive use of them. I can't see why you would want to in any case as they're easy enough to understand and deal with.