Cookie读写问题出现未将对象引用设置到对象的实例？

Question

System.Web.HttpCookie readcookie = Request.Cookies["Info"]; if(readcookie.Values["VotePara"]!=null)//未将对象引用设置到对象的实例？ （）
{

if (readcookie.Values["VotePara"].ToString().IndexOf(Request.QueryString.Get("model_id")+",")==0) {
                   Response.Write("<script>window.alert('投票成功！')</script>");

System.Web.HttpCookie cookie = new System.Web.HttpCookie("Info"); DateTime dt = DateTime.Now; TimeSpan ts = new TimeSpan(365,0,0,0,0); cookie.Expires = dt.Add(ts); cookie.Values.Add("VotePara",Request.QueryString.Get("model_id")+",");
Response.AppendCookie(cookie);                    Response.Write("<script>window.location.href='Model_Show.aspx';</script>"); }
{
                  Response.Write("<script>window.alert('请不要重复投票！')</script>");
}
}

Answer 1

readcookie.Values["VotePara"]!=null)//未将对象引用设置到对象的实例？这行出现错误

Answer 2

if(readcookie!=null){
//然后再判断cookie的值是否为空
}