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);  } }}