PreviousPage 无法取得跨页传递的变量

[telescope]

源页：
<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage/MstPgleftnRight.master" AutoEventWireup="true" CodeFile="List_Teaching_SchoolWorksPackets.aspx.cs" Inherits="LoggedIn_Teaching_List_Teaching_SchoolWorksPackets" %>

<%@ Register src="../../Controls/CtrlschlWksInPackets.ascx" tagname="CtrlschlWksInPackets" tagprefix="uc2" %>
<%@ Register src="../../Controls/CtrlgroupsSchlWkPacketReleaseTo.ascx" tagname="CtrlgroupsSchlWkPacketReleaseTo" tagprefix="uc3" %>

<%@ Register src="../../Controls/CtrlmainMenuLeft.ascx" tagname="CtrlmainMenuLeft" tagprefix="uc1" %>

<asp:Content ID="ContentMenu" ContentPlaceHolderID="CPlcHldleft" Runat="Server">

<uc1:CtrlmainMenuLeft ID="CtrlmainMenuLeft1" runat="server" />

</asp:Content>
<asp:Content ID="ContentMain" ContentPlaceHolderID="CPlcHldright" Runat="Server">
</asp:Content>

源页C#
using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using BLL;
public partial class LoggedIn_Teaching_List_Teaching_SchoolWorksPackets : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{

}
public SqlGuid teachingSchoolWorksPacketID{ get; set; }
protected void ImgBtncreateSchlWkPacket_Click(object sender, ImageClickEventArgs e)
{
string Remark = string.Empty;
string Owner = Profile.UserName;

TeachingSchoolWorksPacket packet = new TeachingSchoolWorksPacket();
this.teachingSchoolWorksPacketID = packet.CreateTeachingSchoolWorksPacket(Owner, Remark);
}
}

目标页：
<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage/MstPgleftnRight.master" AutoEventWireup="true" CodeFile="Edit_SchoolWorksInPacket.aspx.cs" Inherits="LoggedIn_Teaching_Edit_SchoolWorksInPacket" %>

<%@ PreviousPageType VirtualPath="~/LoggedIn/Teaching/List_Teaching_SchoolWorksPackets.aspx" %>

<%@ Register src="../../Controls/CtrlLoggedInLeft.ascx" tagname="CtrlLoggedInLeft" tagprefix="uc1" %>

<asp:Content ID="ContentLeft" ContentPlaceHolderID="CPlcHldleft" Runat="Server">
</asp:Content>
<asp:Content ID="ContentMain" ContentPlaceHolderID="CPlcHldright" Runat="Server">
</asp:Content>

目标页C#
using System;
using System.Collections.Generic;
using System.Data.SqlClient;
using System.Data.SqlTypes;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;


public partial class LoggedIn_Teaching_Edit_SchoolWorksInPacket : System.Web.UI.Page
{

/* 业务逻辑:判断是否存在作业包号
* 如果存在作业包号,列出作业包内作业项
* 如果不存在作业包号,创建作业包
* */



protected void Page_Load(object sender, EventArgs e)
{
if (Page.PreviousPage != null)
{
this.teachingSchoolWorksPacketID = PreviousPage.teachingSchoolWorksPacketID;
}
}
public SqlGuid teachingSchoolWorksPacketID { get; set; }

}

划下划线的那段在VS2008编辑时，总是出波浪线,并且说：“System.Web.UI.Page不包含teachingSchoolWorksPacketID的定义，并且找不到可接受类型为System.Web.UI.Page的第一个参数的扩展方法teachingSchoolWorksPacketID是否缺少Using指令或程序集引用？”

我个人认为，问题不是出在MastPage页的使用上，就是出在用户控件的使用上，请达人指点，在这种情况下，如何成功跨页传递这个变量？ 首先我不想用Session，其次因为变量是SqlGuid型，所以也无法用QuerryString来传递。

[wuyq11]

public String txt
{
get
{
return text.Text;
}
}
<%@ PreviousPageType VirtualPath="~/Page1.aspx" %>
PreviousPageType 指令会导致页的 PreviousPage 属性被类型化为源页类。
在目标页代码中，使用 PreviousPage 属性的强类型成员读取源代码属性。
Label1.Text = PreviousPage.txt;