private int VoteCount;
    protected void Page_Load(object sender, EventArgs e)
    {
        if (!Page.IsPostBack)
        {
            VoteClassDataContext db = new VoteClassDataContext();
            var votes = (from v in db.VoteItem select v.ItemCount).Sum();
            if(votes. hasValue)
            VoteCount= votes.Value;
        }
    }

错误提示:
“int”不包含“hasValue”的定义，并且找不到可接受类型为“int”的第一个参数的扩展方法“hasValue”(是否缺少 using 指令或程序集引用?)    

请各位大虾指教!