When we use abstract class

An abstract class is a just like a template/definition of methods and variables of a class that contains one or more abstracted methods. Abstract classes are used in all common object-oriented programming (OOP) languages (C++, C# and VB.NET, Java).

Objects or classes may be abstracted, which means that they are summarized into characteristics that are relevant to the current program’s operation.

// Abstract class

abstract class Animal

{

// Abstract method (does not have a body)

public abstract void animalSound();

// Regular method

public void sleep()

{

Console.WriteLine("Zzz");

}

}

// Derived class (inherit from Animal)

class Pig : Animal

{

public override void animalSound()

{

// The body of animalSound() is provided here

Console.WriteLine("The pig says: wee wee");

}

}

class Program

{

static void Main(string[] args)

{

Pig myPig = new Pig(); // Create a Pig object

myPig.animalSound(); // Call the abstract method

myPig.sleep(); // Call the regular method

}

}

Abstract classes are created by class library owners/creators who wants certain functionality implemented by the developers who wants to inhertite his/her class library classes. Abstract classes don't implement any functionality. They just define certail abstract members that must be implemented by the derived classes.

 

In typical Windows and Web applications, you will probably never use abstract classes, unless you're building libraries and components.

 

 

 

https://www.youtube.com/watch?v=7amjs2y_dgo

 

https://www.youtube.com/watch?v=yyU3bXyc_oU 

 

Hope this helps 

I think you will easily find this answer on google.

 

When two classes share the same properties or method the common denominator is your abstract class. 

 

Please visit below link: https://msdn.microsoft.com/en-in/library/scsyfw1d(v=vs.71).aspx