The Ultimate Guide to a One-Stop Solution to C# Interface

The word interface describes an abstract type that holds no data but defines behaviors as method signatures in various object-oriented languages, particularly those lacking multiple inheritances. A class that declares that it implements a C# interface is said to have code and data for all the C# interface's functions.

This tutorial on C# Interface is focused on guiding you through the complete fundamentals of the C# interfaces. You will learn the functionalities of the C# interfaces through the practical examples in this tutorial.

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What Is a C# Interface?

Interface in C# is a blueprint of a class. It is like an abstract class because all the methods declared inside the interface are abstract methods. It cannot have a method body and cannot be instantiated.

You declare an interface with a capital letter I in front of the name.

Syntax:

public interface IDemo

{

int sum();

}

After understanding what C# Interface is, you will explore the need for Interfaces.

Why Do You Need C# Interface?

Since you cannot use inheritance with classes in C#, to overcome this limitation, you must employ interfaces. Interfaces are used to build the loosely-coupled applications, which means that components are not dependent on each other, and any altercation will not impact the application itself.

interface-need-img-1

Let's say, for example, there are two classes: drawable and shape. Now, this drawable class depends on the shape class since it can only draw shapes if said shape is defined in the class. This dependency is due to them being tightly coupled.

interface-need-img-2

Now let's say you have an interface drawable. Now this interface can easily communicate with different classes, and it will not affect the main goal to draw the shape. Because now dependency is loosely coupled.

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Implementation of C# Interface

You will implement interfaces using C# language in visual studio code. 

Code:

using System;

public interface IDrawable

{

    void draw();

}

public class Rectangle: IDrawable

{

    public void draw()

    {

        Console.WriteLine("Drawing Rectangle..");

    }

}

public class Circle: IDrawable

{

    public void draw()

    {

        Console.WriteLine("Drawing Circle..");

    }

}

public class Test

{

    public static void Main()

    {

        IDrawable d;

        d= new Rectangle();

        d.draw();

        d= new Circle();

        d.draw();

    }

}

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And this is all for the C# Interface tutorial, and now this write-up will discuss the next steps to understand C# Programming.

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Next Steps

"C# Web API" can be your next concept to learn. The Web API framework is a powerful tool for creating HTTP-enabled service APIs that expose data and services. It may be viewed via browsers, mobile devices, desktop computers, and tablets, among other clients. Because it is an HTTP service, it may reach a large number of users.

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Do you have any questions about this C# Interface tutorial? Please mention them in the comments section at the base of this page. Our experts will be glad to reply to your questions as early as possible!

About the Author

Kartik MenonKartik Menon

Kartik is an experienced content strategist and an accomplished technology marketing specialist passionate about designing engaging user experiences with integrated marketing and communication solutions.

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