为什么传递过来的参数为NULL
protected void Page_Load(object sender, EventArgs e){
if (!Page.IsPostBack)
{
VoteClassDataContext db = new VoteClassDataContext();
var votes = (from v in db.VoteItem where v.TitleID == Int32.Parse(
Request.QueryString["titleid"].ToString()) select v.ItemCount).Sum();
VoteCount = votes;
}
}
错误提示：用户代码未处理 System.NullReferenceException
Message="未将对象引用设置到对象的实例。"
