Create/Retrieve Cookie in ASP.NET

Below example show you how to,

Check cookies is null
Create new cookies
Read cookie

string computerID = string.Empty; //string variable

if (Request.Cookies["webSiteUnique"] == null) // check cookie is null

{ 

 HttpCookie uniq = new HttpCookie("webSiteUnique"); // create new cookie named "webSiteUnique"

 computerID = "1"; 

 uniq.Value = computerID; // set cookie value

 Response.Cookies.Add(uniq); // add newly created cookie to the list of cookies

} 

else 

{ 

 computerID = Request.Cookies["webSiteUnique"].Value; //read cookie value

}