What is Cookie and how many types of Cookies in Asp.Net

 Cookie: Cookie is a small amount of memory used by web server within client system.

•  The main purpose is maintaining personal information of client within Client system to reduce burden  on server.

   cookie can be classified into two types

1.   In-Memory Cookie
2. Persistent Cookie        

 In-Memory Cookie : The Cookie placed within browser process memory is called In-Memory Cookie

• It is temporary Cookie specific to browser instance. Once browser will be closed ,Cookie will be erased.
• Cookie data will be accessible to all the web pages with client request.
• .Net providing HTTPCookie class for sending Cookie or Reading Cookie

Sending Cookie :

example: Httpcookie obj= new httipcookie("n")

                                           obj.value="100";

//Cookie can represent only String data.

      Response.AppendCookie(obj);

//It will send cookie to client Browser.

Reading Cookie submitted by Client (Browser) :

  

   Example:   HttpCookie obj=null;

                         obj=Request.Cookie["n"];

//It returns cookie class object 

//If cookie is available with request

If(obj==null)

  //no cookie submitted

else

obj.value

//returs Cookie value

Persistent Cookie :  Cookie placed with in hard disk memory of client system is called persistent cookie.

• This will be maintained by client system with particular life time .[Life time will be 1 min,1 hour, 1 year .........]
• Once Life time is finished cookie will be erased by client system operating system.

example:  Httpcookie obj = new Httpcookie("n");

                                           obj.value="100";

                     obj.expires=DateTime.Now.AddDay(2)  // lifetime is 2 days

                       Response.AppendCookie(obj);

//Persistent cookie= in-memory cookie + Life time