#region 添加到购物车AddShoppingCar
/// <summary>
/// 添加到购物车AddShoppingCar
/// </summary>
/// <param name="num">数量 如果存在产品 负数是减少
/// 正数是增加  如果不存在  直接增加</param>
/// <param name="id">货物ID</param>
/// <param name="expires">cookies保存的天数</param>
/// <remarks>这里的方法就是把在原有的Cookie基础上判断是否有
/// 这个产品 如果有 在原有数量上增加 没有 就直接增加 如果是负
/// 数 就是减少 如果负数的数量大于等于
/// 原有数量 设置为0 对应后面的读出操作</remarks>
public static void AddShoppingCar(string num, string id, int expires)
{
    if (System.Web.HttpContext.Current.Request.Cookies["Products"] != null)
    {
        System.Web.HttpCookie cookie;
        string cookievalue = System.Web.HttpContext.Current.Request.Cookies["Products"].Value;
        if (System.Web.HttpContext.Current.Request.Cookies["Products"].Values[id.ToString()] == null)
        {
            cookievalue = cookievalue + "&" + id + "=" + num;

}
        else
        {
            int num1 = int.Parse(System.Web.HttpContext.Current.Request.Cookies["Products"].Values[id.ToString()].ToString()) + int.Parse(num);
            if (num1 > 0)
            {
                System.Web.HttpContext.Current.Request.Cookies["Products"].Values[id.ToString()] = num1.ToString();
            }
            else
            {
                System.Web.HttpContext.Current.Request.Cookies["Products"].Values[id.ToString()] = "0";
            }
            cookievalue = System.Web.HttpContext.Current.Request.Cookies["Products"].Value;
        }
        cookie = new System.Web.HttpCookie("Products", cookievalue);
        if (expires != 0)
        {
            DateTime dt = DateTime.Now;
            TimeSpan ts = new TimeSpan(expires, 0, 0, 20);
            cookie.Expires = dt.Add(ts);
        }
        System.Web.HttpContext.Current.Response.AppendCookie(cookie);
    }
    else
    {
        System.Web.HttpCookie newcookie = new HttpCookie("Products");
        if (expires != 0)
        {
            DateTime dt = DateTime.Now;
            TimeSpan ts = new TimeSpan(expires, 0, 0, 20);
            newcookie.Expires = dt.Add(ts);
        }
        newcookie.Values[id.ToString()] = num;
        System.Web.HttpContext.Current.Response.AppendCookie(newcookie);
    }
}
#endregion

#region 添加到购物车AddShoppingCar
/// <summary>
/// 添加到购物车AddShoppingCar
/// </summary>
/// <param name="num">数量 如果存在产品 负数是减少
/// 正数是增加  如果不存在  直接增加</param>
/// <param name="dt">
/// 循环读出来的DATATABLE
/// </param>
/// <param name="id">货物ID</param>
/// <param name="expires">cookies保存的天数</param>
/// <remarks>这里的方法就是把在原有的Cookie基础上判断是否有
/// 这个产品 如果有 在原有数量上增加 没有 就直接增加 如果是负
/// 数 就是减少 如果负数的数量大于等于
/// 原有数量 设置为0 对应后面的读出操作</remarks>
public static void AddShoppingCar(DataTable dt, int expires)
{

if (System.Web.HttpContext.Current.Request.Cookies["Products"] != null)
        {
            System.Web.HttpCookie cookie;
            string cookievalue = System.Web.HttpContext.Current.Request.Cookies["Products"].Value;
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                if (System.Web.HttpContext.Current.Request.Cookies["Products"].Values[dt.Rows[i]["id"].ToString().ToString()] == null)
                {
                    cookievalue = cookievalue + "&" + dt.Rows[i]["id"].ToString() + "=" + dt.Rows[i]["num"].ToString();
                }
                else
                {
                    int num1 = int.Parse(System.Web.HttpContext.Current.Request.Cookies["Products"].Values[dt.Rows[i]["id"].ToString().ToString()].ToString()) + int.Parse(dt.Rows[i]["num"].ToString());
                    if (num1 > 0)
                    {
                        System.Web.HttpContext.Current.Request.Cookies["Products"].Values[dt.Rows[i]["id"].ToString().ToString()] = num1.ToString();
                    }
                    else
                    {
                        System.Web.HttpContext.Current.Request.Cookies["Products"].Values[dt.Rows[i]["id"].ToString().ToString()] = "0";
                    }
                    cookievalue = System.Web.HttpContext.Current.Request.Cookies["Products"].Value;
                }
            }
            cookie = new System.Web.HttpCookie("Products", cookievalue);
            if (expires != 0)
            {
                DateTime time1 = DateTime.Now;
                TimeSpan ts = new TimeSpan(expires, 0, 0, 20);
                cookie.Expires = time1.Add(ts);
            }
            System.Web.HttpContext.Current.Response.AppendCookie(cookie);
        }
        else
        {
            System.Web.HttpCookie newcookie = new HttpCookie("Products");
            if (expires != 0)
            {
                DateTime time1 = DateTime.Now;
                TimeSpan ts = new TimeSpan(expires, 0, 0, 20);
                newcookie.Expires = time1.Add(ts);
            }
            for (int i = 0; i < dt.Rows.Count; i++)
            {
                newcookie.Values[dt.Rows[i]["id"].ToString()] = dt.Rows[i]["num"].ToString();
            }
            System.Web.HttpContext.Current.Response.AppendCookie(newcookie);
        }
   
}
#endregion

#region 根据ID删除产品RemoveShoppingCar
/// <summary>
/// 根据ID删除产品RemoveShoppingCar
/// </summary>
/// <param name="id">产品ID</param>
/// <remarks>
/// 就是设置商品数量为0
/// 本来增加方法可以实现
/// 但是需要读出来原有数量
/// 所以为了避免繁琐 有此方法
/// </remarks>
public static void RemoveShoppingCar(string id)
{
    if (System.Web.HttpContext.Current.Request.Cookies["Products"] != null && System.Web.HttpContext.Current.Request.Cookies["Products"].Values[id] != null)
    {
        System.Web.HttpCookie cookie;
        System.Web.HttpContext.Current.Request.Cookies["Products"].Values[id] = "0";
        string cookievalue = System.Web.HttpContext.Current.Request.Cookies["Products"].Value;
        cookie = new System.Web.HttpCookie("Products", cookievalue);
        System.Web.HttpContext.Current.Response.AppendCookie(cookie);
    }
}
#endregion

#region 删除购物车RemoveShoppingCar
/// <summary>
/// 删除购物车RemoveShoppingCar
/// </summary>
/// <remarks>
/// 使购物车的Cookie为空
/// </remarks>
public static void RemoveShoppingCar()
{
    if (System.Web.HttpContext.Current.Request.Cookies["Products"] != null && System.Web.HttpContext.Current.Request.Cookies["Products"].Values.Count != 0)
    {
        System.Web.HttpContext.Current.Request.Cookies["Products"].Expires = System.DateTime.Now.AddHours(-1);
        System.Web.HttpContext.Current.Response.AppendCookie(System.Web.HttpContext.Current.Request.Cookies["Products"]);
    }
}
#endregion

#region 根据ID修改产品UpdateShoppingCar
/// <summary>
/// 根据ID修改产品UpdateShoppingCar
/// </summary>
/// <param name="id">产品ID</param>
/// <param name="num">产品数量</param>
/// <remarks>
/// 更新产品的数量
/// </remarks>
public static void UpdateShoppingCar(string id,string num)
{
    if (System.Web.HttpContext.Current.Request.Cookies["Products"] != null && System.Web.HttpContext.Current.Request.Cookies["Products"].Values[id] != null)
    {
        System.Web.HttpCookie cookie;
        System.Web.HttpContext.Current.Request.Cookies["Products"].Values[id] = num;
        string cookievalue = System.Web.HttpContext.Current.Request.Cookies["Products"].Value;
        cookie = new System.Web.HttpCookie("Products", cookievalue);
        System.Web.HttpContext.Current.Response.AppendCookie(cookie);
    }
}
#endregion

#region 得到所有的产品列表GetAllChoppingCar
/// <summary>
/// 得到所有的产品列表GetAllChoppingCar
/// </summary>
/// <returns>所有产品的数据集</returns>
/// <remarks>因为对DataTable操作比较方便(个人喜好)
/// 这里是把里面的字符串分割为Datatable</remarks>
public static DataTable GetAllChoppingCar()
{
    if (System.Web.HttpContext.Current.Request.Cookies["Products"] != null && System.Web.HttpContext.Current.Request.Cookies["Products"].Value.Trim() != "")
    {
        DataColumn dcid = new DataColumn("id");
        DataColumn dcnum = new DataColumn("num");
        DataTable dt = new DataTable();
        dt.Columns.Add(dcid);
        dt.Columns.Add(dcnum);
        string[] str = System.Web.HttpContext.Current.Request.Cookies["Products"].Value.Split('&');
        for (int i = 0; i < str.Length; i++)
        {
            DataRow dr = dt.NewRow();
            dr["id"] = (str[i].Split('='))[0].ToString();
            dr["num"] = (str[i].Split('='))[1].ToString();
            if (int.Parse((str[i].Split('='))[1].ToString()) != 0)
            {
                dt.Rows.Add(dr);
            }
        }
        return dt;
    }
    else
    {
        return null;
    }
}
#endregion

#region 关于购物车Cookie里的DataTable的操作GetCookieByDataTable
/// <summary>
/// 关于购物车Cookie里的DataTable的操作GetCookieByDataTable
/// </summary>
/// <param name="dt"></param>
/// <remarks>
/// 把读出来的DataTable转换为字符串
/// 根据的规则是自己定的 &符号是分开产品
/// =号是分开产品ID和产品价格
/// </remarks>
/// <returns></returns>
public static String GetCookieByDataTable(DataTable dt)
{
    String datatable = "";
    if (dt.Rows.Count > 0)
    {
        for (int i = 0; i < dt.Rows.Count; i++)
        {
            datatable = dt.Rows[i]["id"].ToString() + "=" + dt.Rows[i]["num"].ToString() + "&" + datatable;
        }
    }
    return datatable;
}
#endregion

#region 把字符串转换为datatable  GetDataTable
/// <summary>
/// 把字符串转换为datatable  GetDataTable
/// </summary>
/// <param name="datatable"></param>
/// <remarks>
/// 把Cookie里的字符串转换为DataTable
/// 是GetCookieByDataTable的反操作
/// </remarks>
/// <returns></returns>
public static DataTable GetDataTable(string datatable)
{
    DataColumn dcid = new DataColumn("id");
    DataColumn dcnum = new DataColumn("num");
    DataTable dt = new DataTable();
    dt.Columns.Add(dcid);
    dt.Columns.Add(dcnum);
    if (!datatable.StartsWith("&"))
    {
        string[] str = datatable.Split('&');
        for (int i = 0; i < str.Length; i++)
        {
            DataRow dr = dt.NewRow();
            dr["id"] = (str[i].Split('='))[0].ToString();
            dr["num"] = (str[i].Split('='))[1].ToString();
            if (int.Parse((str[i].Split('='))[1].ToString()) != 0)
            {
                dt.Rows.Add(dr);
            }
        }
    }
    else
    {
        DataRow dr = dt.NewRow();
        dr["id"] = (datatable.Split('='))[0].ToString();
        dr["num"] = (datatable.Split('='))[1].ToString();
        if (int.Parse((datatable.Split('='))[1].ToString()) != 0)
        {
            dt.Rows.Add(dr);
        }
    }
    return dt;
}
#endregion

转贴请注明alon发表在http://www.cnblogs.com/alon1982 与2008年12月3号