C#自定义简化cookie类实例

using System;
using System.Web;
namespace DotNet.Utilities
{
 public class CookieHelper
 {
  /// <summary>
  /// 清除指定Cookie
  /// </summary>
  /// <param name="cookiename">cookiename</param>
  public static void ClearCookie(string cookiename)
  {
   HttpCookie cookie = HttpContext.Current.Request.Cookies[cookiename];
   if (cookie != null)
   {
    cookie.Expires = DateTime.Now.AddYears(-3);
    HttpContext.Current.Response.Cookies.Add(cookie);
   }
  }
  /// <summary>
  /// 获取指定Cookie值
  /// </summary>
  /// <param name="cookiename">cookiename</param>
  /// <returns></returns>
  public static string GetCookieValue(string cookiename)
  {
   HttpCookie cookie = HttpContext.Current.Request.Cookies[cookiename];
   string str = string.Empty;
   if (cookie != null)
   {
    str = cookie.Value;
   }
   return str;
  }
  /// <summary>
  /// 添加一个Cookie（24小时过期）
  /// </summary>
  /// <param name="cookiename"></param>
  /// <param name="cookievalue"></param>
  public static void SetCookie(string cookiename, string cookievalue)
  {
   SetCookie(cookiename, cookievalue, DateTime.Now.AddDays(1.0));
  }
  /// <summary>
  /// 添加一个Cookie
  /// </summary>
  /// <param name="cookiename">cookie名</param>
  /// <param name="cookievalue">cookie值</param>
  /// <param name="expires">过期时间 DateTime</param>
  public static void SetCookie(string cookiename, string cookievalue,DateTime expires)
  {
   HttpCookie cookie = new HttpCookie(cookiename)
   {
    Value = cookievalue,
    Expires = expires
   };
   HttpContext.Current.Response.Cookies.Add(cookie);
  }
 }
}