asp.net Cookie操作类

using system;
using system.collections.generic;
using system.linq;
using system.web;
using system.web.security;
using system.web.ui;
using system.web.ui.htmlcontrols;
using system.web.ui.webcontrols;
using system.data;
using system.configuration;

namespace jhgl.smart
{
/// <summary>
/// cookie操作类
/// </summary>
public class cookie
{
/// <summary>
/// 保存一个cookie
/// </summary>
/// <param name="cookiename">cookie名称</param>
/// <param name="cookievalue">cookie值</param>
/// <param name="cookietime">cookie过期时间(小时),0为关闭页面失效</param>
public static void savecookie(string cookiename, string cookievalue, double cookietime)
{
httpcookie mycookie = new httpcookie(cookiename);
datetime now = datetime.now;
mycookie.value = cookievalue;

if (cookietime != 0)
{
//有两种方法，第一方法设置cookie时间的话，关闭浏览器不会自动清除cookie
//第二方法不设置cookie时间的话，关闭浏览器会自动清除cookie ,但是有效期
//多久还未得到证实。
mycookie.expires = now.adddays(cookietime);
if (httpcontext.current.response.cookies[cookiename] != null)
httpcontext.current.response.cookies.remove(cookiename);

httpcontext.current.response.cookies.add(mycookie);
}
else
{
if (httpcontext.current.response.cookies[cookiename] != null)
httpcontext.current.response.cookies.remove(cookiename);

httpcontext.current.response.cookies.add(mycookie);
}
}
/// <summary>
/// 取得cookievalue
/// </summary>
/// <param name="cookiename">cookie名称</param>
/// <returns>cookie的值</returns>
public static string getcookie(string cookiename)
{
httpcookie mycookie = new httpcookie(cookiename);
mycookie = httpcontext.current.request.cookies[cookiename];

if (mycookie != null)
return mycookie.value;
else
return null;
}
/// <summary>
/// 清除cookievalue
/// </summary>
/// <param name="cookiename">cookie名称</param>
public static void clearcookie(string cookiename)
{
httpcookie mycookie = new httpcookie(cookiename);
datetime now = datetime.now;

mycookie.expires = now.addyears(-2);

httpcontext.current.response.cookies.add(mycookie);
}
}
}