A cookie is a small bit of text that accompanies requests and pages as they go between the Web server and browser. The cookie contains information the Web application can read whenever the user visits the site.

Cookies are sent to the browser via the HttpResponse object that exposes a collection called Cookies. You can access the HttpResponse object as the Response property of your Page class. Any cookies that you want to send to the browser must be added to this collection. When creating a cookie, you specify a Name and Value. Each cookie must have a unique name so that it can be identified later when reading it from the browser. Because cookies are stored by name, naming two cookies the same will cause one to be overwritten.

Create/Set Cookie

Response.Cookies["UserId"].Value = "rajesh";
Response.Cookies["UserId"].Expires = DateTime.Now.AddDays(1);

HttpCookie aCookie = new HttpCookie("lastVisit");
aCookie.Value = DateTime.Now.ToString();
aCookie.Expires = DateTime.Now.AddDays(1);
Response.Cookies.Add(aCookie);

Cookies with More Than One Value

Response.Cookies["userInfo"]["UserId"] = "rajesh";
Response.Cookies["userInfo"]["lastVisit"] = DateTime.Now.ToString();
Response.Cookies["userInfo"].Expires = DateTime.Now.AddDays(1);

HttpCookie aCookie = new HttpCookie("userInfo");
aCookie.Values["UserId"] = "rajesh";
aCookie.Values["lastVisit"] = DateTime.Now.ToString();
aCookie.Expires = DateTime.Now.AddDays(1);
Response.Cookies.Add(aCookie);


Limit the Cookie Folder level

HttpCookie appCookie = new HttpCookie("AppCookie");
appCookie.Value = DateTime.Now.ToString();
appCookie.Expires = DateTime.Now.AddDays(1);
appCookie.Path = "/ApplicationTest";
Response.Cookies.Add(appCookie);

Limit the Cookie Domain level

Response.Cookies["domain"].Value = DateTime.Now.ToString();
Response.Cookies["domain"].Expires = DateTime.Now.AddDays(1);
Response.Cookies["domain"].Domain = "domain1.com";

Read the Cookies

Label1.Text = Server.HtmlEncode(Request.Cookies["userName"].Value);

Read and convert to Datetime

DateTime dt;
dt = DateTime.Parse(Request.Cookies["userInfo"]["lastVisit"]);

Delete the Cookie

var aCookie = new HttpCookie("UserInfo");
aCookie.Expires = DateTime.Now.AddDays(-1);
Response.Cookies.Add(aCookie);