C# Interface Tutorial for Beginners

Interfaces in C# (For Beginners)

An interface contains only the signatures of methods, properties, events or indexers/delegates. A class or struct that implements the interface must implement the members of the interface that are specified in the interface definition.

Example Imagine that you have a pizza store. You know that all pizzas need to be ordered, prepared, baked and boxed. Well, you can define this common behavior into an interface.

C# - Learning to use Interfaces effectively

Create interface by right click on application - > Add new item -> Interface1.cs (named IPizza)

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace consoleapp

{

   public interface IPizza

    {

        void order();      

        void prepare();

        void baked();

        void box();

    }

}

I have different kinds of pizzas implement in that interface. When you implement an interface, you're forcing that class to have the same methods and parameters as the interface, for example:

Creating a Class to inherit the interface (IPizza)

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace consoleapp

{

    class DoubleCheesePizza:IPizza

    {

        public void order()

        {

            Console.WriteLine("order");

        }

        public void prepare()

        {

            Console.WriteLine("prepare");

        }

        public void baked()

        {

            Console.WriteLine("baked");

        }

        public void box()

        {

            Console.WriteLine("box");

        }

    }

   

}

Call it from main() program

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

namespace consoleapp

{

    class Program

    {

        static void Main(string[] args)

        {

            DoubleCheesePizza obj = new DoubleCheesePizza();

            obj.order();

            obj.prepare();

            obj.baked();

            obj.box();

            Console.ReadKey();

        }

    } 

}

Advantage of using Interface

• Supports multiple inheritance(Single Class can implement multiple interfaces).
• Contains only incomplete method.
• Can not Contains data members/variables/fields.
• By Default interface members is public (We Can not set any access modifier into interface members).
• Interface can not contain constructors.

Download the source code click here

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