CooieHelper类，方法 清除cookie退出登录

        /// <summary>
        /// 为HttpCookie创建kye,hash存cookie对象的key和值
        /// </summary>
        /// <param name="strKey"></param>
        /// <param name="hash"></param>
        public static void AddCookie(string strKey, Hashtable hash)
        {
            HttpCookie cookie = HttpContext.Current.Request.Cookies[strKey];
            if (cookie != null)
            {
                cookie.Expires = DateTime.Now.AddDays(-1);
                HttpContext.Current.Response.Cookies.Add(cookie);
            }
            if (hash != null)
            {
                cookie = new HttpCookie(strKey);
                foreach (DictionaryEntry de in hash)
                {
                    cookie.Values.Add(de.Key.ToString(), de.Value.ToString());
                }
                cookie.Expires = DateTime.Now.AddHours(5);
                HttpContext.Current.Response.Cookies.Add(cookie);
            }
        }

        /// <summary>
        /// 判断cook对象是否为空
        /// </summary>
        /// <param name="strKey"></param>
        /// <returns></returns>
        public static HttpCookie GetCookie(string strKey)
        {
            HttpCookie cookie = HttpContext.Current.Request.Cookies[strKey];
            if (cookie != null)
            {
                return cookie;

            }
            else
            {
                return null;
            }

        }

/// <summary>
///推出清除Cookie 
/// </summary>
 protected void LinkExit_Click(object sender, EventArgs e)
{

　　　　HttpCookie cookie = Request.Cookies["employee"];

if (cookie != null)
{
cookie.Expires = DateTime.Today.AddDays(-1);
Response.Cookies.Add(cookie);
}
Response.Redirect("../Login.aspx");

}