Difference in coping object using = and MemberwiseClone

Question

I have question regarding copying object using = operation and by shallow copy (MemberwiseClone)

I heard earlier that = operator also uses MemberwiseClone behind the scene but when I tested I got different result.

 

For Example:

class A

{

   string Brand;

   int Rating;

}

 

A a1 = new A();

a1.Brand = "ABC";

a1.Rating = 1;

 

A a2 = a1;

a2.Brand = "PQR";

a2.Rating = 2;

 

Console.WriteLine("Origional Object");

Console.WriteLine("Brand: {0}, Rating {1}", a1.Brand, a1.Rating); //Prints Brand: PQR, Rating 2

 

Console.WriteLine("Copied Object");

Console.WriteLine("Brand: {0}, Rating {1}", a2.Brand, a2.Rating); //Prints Brand: PQR, Rating 2

 

When I copy using MemberwiseClone, I find result as below.

 Brand: ABC, Rating 1

 Brand: PQR, Rating 2  

 

May I know when I copy object using = then why source object is also getting changed even for changing primitive types in target object where not when copying using MemberwiseClone?