ASP.NET includes two intrinsic cookie collections. The collection accessed through the Cookies collection of HttpRequest contains cookies transmitted by the client to the server in the Cookie header. The collection accessed through the Cookies collection of HttpResponse contains new cookies created on the server and transmitted to the client in the Set-Cookie header.

After you add a cookie by using the HttpResponse..::.Cookies collection, the cookie is immediately available in the HttpRequest..::.Cookies collection, even if the response has not been sent to the client.

The following example creates a new cookie named LastVisit, sets the value of the cookie to the current date and time, and adds the cookie to the current cookie collection. All cookies in the cookie collection are sent to the client in the Set-Cookie header with the HTTP output stream.

Dim MyCookie As New HttpCookie("LastVisit")
Dim now As DateTime = DateTime.Now

MyCookie.Value = now.ToString()
MyCookie.Expires = now.AddHours(1)

Response.Cookies.Add(MyCookie)
   

HttpCookie MyCookie = new HttpCookie("LastVisit");
DateTime now = DateTime.Now;

MyCookie.Value = now.ToString();
MyCookie.Expires = now.AddHours(1);

Response.Cookies.Add(MyCookie);
   

.NET Framework

Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2

Reference