C# Interface vs Inheritance

This article is a quick review of C# interface vs inheritance. Both interfaces and inheritance allow you to define a set of behaviors that a class can implement. However, there are some key differences between the two.

Inheritance is a mechanism for creating a new class that is a variation or extension of an existing class. When a class inherits from another class, it can access all of the properties, methods, and fields of the parent class, as well as add new ones. Inheritance helps us to create class hierarchies, where classes at the top of the hierarchy are more general and classes at the bottom of the hierarchy are more specific.

On the other hand, an interface defines a set of methods, properties, and events that a class must implement. An interface only specifies the behavior that a class must have, but it doesn’t provide any implementation. In other words, an interface is a contract that a class must fulfill. By the way, did you know that we offer a unique online course that boosts your C# career? Check it out here!

One key advantage of interfaces is that they allow classes to implement multiple interfaces, whereas a class can only inherit from a single parent class. This makes interfaces very useful for creating flexible and extensible code.

Inheritance allows us to hierarchy of classes that share common functionality, while interfaces define a set of behaviors that a class must implement. Both inheritance and interfaces have their own use cases and advantages, and choosing between the two depends on the specific requirements of your application.

 

Let’s see some code examples to illustrate the differences between inheritance and interfaces in C#.

Inheritance

Inheritance allows you to create a new class that is a variation or extension of an existing class. When a class inherits from another class, it can access all of the properties, methods, and fields of the parent class, as well as add new ones.

Here is an example:

 

In this example, Cat inherits from Animal, which means that it can access the Eat() method of Animal. However, Cat overrides the Eat() method to provide its own implementation.

 

Interfaces

Interfaces define a set of methods, properties, and events that a class must implement. An interface only specifies the behavior that a class must have, but it doesn’t provide any implementation.

Here is an example:

 

In this example, IShape is an interface that defines two methods: Area() and Perimeter(). The Rectangle class implements the IShape interface, which means that it must provide implementations for both of these methods. Note that the IShape interface doesn’t provide any implementation for these methods – it only defines their signatures.

 

When to use which?

Both inheritance and interfaces have their own use cases and advantages, and choosing between the two depends on the specific requirements of your application.

Inheritance

Inheritance is a good choice when you want to create a class hierarchy that shares common functionality. Here are some scenarios where you might want to use inheritance:

• When you want to reuse code from an existing class and add new functionality to it.
• When you want to create a specialized version of a general class.
• When you want to implement the “is-a” relationship between classes, where a subclass is a more specific type of its superclass.

 

Interfaces

Interfaces are a good choice when you want to define a set of behaviors that multiple classes can implement. Here are some scenarios where you might want to use interfaces:

• When you want to create a contract that multiple classes must fulfill.
• When you want to decouple a class from its implementation details, so that you can change the implementation without affecting the rest of the code.
• When you want to create a flexible and extensible architecture that allows for different implementations of the same behavior.
• It’s also worth noting that in C#, a class can implement multiple interfaces, but it can only inherit from a single parent class. This means that interfaces provide more flexibility and can help you create more modular and reusable code.

 

Summary

In summary, inheritance and interfaces have different use cases and advantages, and the choice between the two depends on the specific requirements of your application. In general, inheritance is a good choice when you want to create a class hierarchy with shared functionality, while interfaces are a good choice when you want to define a set of behaviors that multiple classes can implement. If you want to skyrocket your C# career, check out our powerful ASP.NET full-stack web development course that also covers test-driven development.