On The Care and Handling of Cookies

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;

namespace InteractiveAspNet
{
	/// <summary>
	/// Summary description for AspNetCookies.
	/// </summary>
	public class AspNetCookies : System.Web.UI.Page
	{
		protected System.Web.UI.WebControls.Label myRequestCookie;
		protected System.Web.UI.WebControls.Button btnSetCookie;
		protected System.Web.UI.WebControls.Button btnClearCookie;
		protected System.Web.UI.WebControls.Button btnDoNothing;
	
		private void Page_Load(object sender, System.EventArgs e)
		{
			if (Request.Cookies["TestCookie"] != null)
				Response.Cookies.Set(Request.Cookies["TestCookie"]);
			else
				Response.Cookies.Set(new HttpCookie("TestCookie", ""));

			Response.Cookies["TestCookie"].Expires = DateTime.Now.AddYears(30);

			// Display the Request cookie on the page
			if (Response.Cookies["TestCookie"].Value == "")
				myRequestCookie.Text = "Cookie is null";
			else
				myRequestCookie.Text = Request.Cookies["TestCookie"].Value;
		}

		#region Web Form Designer generated code
		override protected void OnInit(EventArgs e)
		{
			//
			// CODEGEN: This call is required by the ASP.NET Web Form Designer.
			//
			InitializeComponent();
			base.OnInit(e);
		}
		
		/// <summary>
		/// Required method for Designer support - do not modify
		/// the contents of this method with the code editor.
		/// </summary>
		private void InitializeComponent()
		{    
			this.btnSetCookie.Click += new System.EventHandler(this.btnSetCookie_Click);
			this.btnClearCookie.Click += new System.EventHandler(this.btnClearCookie_Click);
			this.btnDoNothing.Click += new System.EventHandler(this.btnDoNothing_Click);
			this.Load += new System.EventHandler(this.Page_Load);

		}
		#endregion

		protected override void OnPreRender(System.EventArgs e)
		{
			if (Response.Cookies["TestCookie"].Value == Request.Cookies["TestCookie"].Value)
				Response.Cookies.Remove("TestCookie");

			base.OnPreRender(e);
		}

		private void btnSetCookie_Click(object sender, System.EventArgs e)
		{
			// Set up a cookie and redirect to this page to pick it up for display
			Response.Cookies["TestCookie"].Value = "Cookie is set";
			Response.Redirect("AspNetCookies.aspx");
		}

		private void btnClearCookie_Click(object sender, System.EventArgs e)
		{
			// Expire the cookie and redirect to this page to display a message
			Response.Cookies["TestCookie"].Expires = DateTime.Now.AddYears(-30);
			Response.Redirect("AspNetCookies.aspx");
		}

		private void btnDoNothing_Click(object sender, System.EventArgs e)
		{
			// Do absolutely nothing except redirect to simulate moving to another page
			Response.Redirect("AspNetCookies.aspx");
		}
	}
}