网站项目中Profile的引用有关问题

<?xml version="1.0"?><!--  有关如何配置 ASP.NET 应用程序的详细信息，请访问  http://go.microsoft.com/fwlink/?LinkId=169433  --><configuration xmlns="http://schemas.microsoft.com/.NetConfiguration/v2.0">    <system.web>            <authorization>        <deny users="?" />      </authorization>      <authentication mode="Forms" />      <compilation debug="true" targetFramework="4.0"/>      <membership defaultProvider="SqlProvider" userIsOnlineTimeWindow="15">        <providers>          <clear />          <add          name="SqlProvider"          type="System.Web.Security.SqlMembershipProvider"          connectionStringName="NorthwindConnectionString"          applicationName="northWind"          enablePasswordRetrieval="false"          enablePasswordReset="true"          requiresQuestionAndAnswer="true"          requiresUniqueEmail="true"          passwordFormat="Hashed" />        </providers>      </membership>            <roleManager defaultProvider="SqlProvider"        enabled="true"        cacheRolesInCookie="true"        cookieName=".ASPROLES"        cookieTimeout="30"        cookiePath="/"        cookieRequireSSL="false"        cookieSlidingExpiration="true"        cookieProtection="All" >        <providers>          <add          name="SqlProvider"          type="System.Web.Security.SqlRoleProvider"          connectionStringName="NorthwindConnectionString"          applicationName="northWind" />        </providers>      </roleManager>    </system.web>  <connectionStrings>    <add name="NorthwindConnectionString" connectionString="Data Source=XXX-PC;Initial Catalog=aspnetdb;Integrated Security=True;"      providerName="System.Data.Sqlclient" />    [color=#FF0000]<profile>      <properties>        <add name="Country"/>        <add name="Visits" type="System.Int32" defaultValue="0"/>        <add name="LastVisit" type="System.DateTime"/>      </properties>    </profile>[/color]    <add name="EventsConnectionString" connectionString="Data Source=XXX-PC;Initial Catalog=BegVCSharpEvents;Integrated Security=True"      providerName="System.Data.SqlClient" />  </connectionStrings>   </configuration>

using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;public partial class ProfileDemo : System.Web.UI.Page{    protected void Page_Load(object sender, EventArgs e)    {        if (!Page.IsPostBack)        {            DropDownListCountries.SelectedValue = Profile.Country;        }        LabelLastVisit.Text = Profile.LastVisit.ToLongTimeString();        LabelVisitCount.Text = Profile.Visits.ToString();        LabelSelectedCountry.Text = Profile.Country;        Profile.Visits++;        Profile.LastVisit = DateTime.Now;        Profile.Save();    }    protected void onCountrySelection(object sender, EventArgs e)    {          Profile.Country = this.DropDownListCountries.SelectedItem.Value;          Profile.Save();     }}