C# Interface - c# - c# tutorial - c# net
What is the use of interface in C# ?
- Interface in C# is a blueprint of a class. It is like abstract class because all the methods which are declared inside the interface are abstract methods.
- It cannot have method body and cannot be instantiated.
- It is used to achieve multiple inheritance which can't be achieved by class.
- It is used to achieve fully abstraction because it cannot have method body.
- Its implementation must be provided by class or struct.
- The class or struct which implements the interface, must provide the implementation of all the methods declared inside the interface.
Interface
C# interface example
- Let's see the example of interface in C# which has draw() method. Its implementation is provided by two classes: Rectangle and Circle.
using System;
public interface Drawable
{
void draw();
}
public class Rectangle : Drawable
{
public void draw()
{
Console.WriteLine("drawing rectangle...");
}
}
public class Circle : Drawable
{
public void draw()
{
Console.WriteLine("drawing circle...");
}
}
public class TestInterface
{
public static void Main()
{
Drawable d;
d = new Rectangle();
d.draw();
d = new Circle();
d.draw();
}
}
C# examples - Output :
drawing rectangle...
drawing circle…
Note: Interface methods are public and abstract by default. You cannot explicitly use public and abstract keywords for an interface method.
learn c# tutorial - Abstract vs Interface Csharp in c# Example
using System;
public interface Drawable
{
public abstract void draw();//Compile Time Error
}