int counter,time;
        if (Request.Cookies["time"] == null)
        {
            counter = 1;
        }
        else
        {
            counter = int.Parse(Request.Cookies["main"]["time"].ToString());
            
            counter += 1;
        }
        Response.Write("您是第" + counter + "次访问本站<br>");
        Response.Write("您上次访问时间是" + Request.Cookies["main"]["times"]);
        HttpCookie mycookie = new HttpCookie("main");
        mycookie["time"] = counter.ToString();
        mycookie.Expires = DateTime.Now.AddDays(30d);
        Response.Cookies.Add(mycookie);
        Response.Cookies["main"]["times"] =time .ToString(DateTime.Now);


错误    1    与“int.ToString(string)”最匹配的重载方法具有一些无效参数   
错误    2    参数“1”: 无法从“System.DateTime”转换为“string”

能讲得详细点么？