ASP.Net MVC检查用户在aspnet Membership中的角色

<%@ Control Language="C#" Inherits="System.Web.Mvc.ViewUserControl" %>
<%
    if (Request.IsAuthenticated) {
%>
        Welcome <b><%= Html.Encode(Page.User.Identity.Name) %></b>!
        [ <%= Html.ActionLink("Log Off", "LogOff", "Account") %> ]
        <br /> 
<% if(User.IsInRole("Administrator")) { %>
        <br />
        <%= Html.ActionLink("Home", "Index", "Home") %> | <%= Html.ActionLink("About", "About", "Home") %> | <%= Html.ActionLink("UserControl","UserControl","Account")%>
        <% } else { %>
        <br />
        <%= Html.ActionLink("Home", "Index", "Home") %> | <%= Html.ActionLink("About", "About", "Home") %>
     <%} %>

我想检查用户的角色,如果它是管理员,只有这样用户才能看到指向用户控件的链接 “'Data.User'不包含'IsInRole'的定义”