未将对象引用设置到对象实例我在网上下了个网站,运行后下面的这段代码提示未将对象引用设置到对象实例cart.MigrateShoppingCartItems(Session["AnonUID"].ToString(), UserName.Text);
是在登录/注册部分出现差错的,就是我登录以前注册的账户,会提示上述错误,出现错误的完整的代码如下:
<%@ Page Language="C#" Inherits="IBuyAdventure.PageBase" src="components/stdpage.cs" %>
<%@ Import Namespace="System.Web.Security" %>
<%@ Register TagPrefix="IBA" TagName="Header" Src="UserControl/Header.ascx" %>
<%@ Register TagPrefix="IBA" TagName="Categories" Src="UserControl/Categories.ascx" %>
<html>
   <head>
     <title>达也电子商务网</title>
   </head>
	<script language="C#" runat="server">
		void Page_Load(Object sender, EventArgs e) {
			// Store Return Url in Page State
			if (Request.QueryString["ReturnUrl"] != null)
			{
				ReturnUrl.Value = Request.QueryString["ReturnUrl"];
				((HyperLink)RegisterUser).NavigateUrl = "Register.aspx?ReturnUrl=" + ReturnUrl.Value;
			}
		}
		void LoginBtn_Click(Object sender, EventArgs e)	{
			IBuyAdventure.UsersDB users = new IBuyAdventure.UsersDB(getConnStr());
			IBuyAdventure.CartDB cart = new IBuyAdventure.CartDB(getConnStr());
			if (users.ValidateLogin(UserName.Text, Password.Text)) {
				// Migrate any temporary shopping cart items to logged-in username
				cart.MigrateShoppingCartItems(Session["AnonUID"].ToString(), UserName.Text);
				// Set Client Authentication Cookie
				FormsAuthentication.RedirectFromLoginPage(UserName.Text, Persist.Checked);
			}
			else {
				Message.Text = "注册失败,请输入正确资料再次注册.";
			}
		}
	</script>
   <body background="images/back_sub.gif">
     <form method=post action="Login.aspx" runat="server">
       <font face="Verdana, Arial, Helvetica" size="2">
         <table border="0">
           <tr>
             <td colspan="5">
               <IBA:Header id="Header" runat="server"/>
             </td>
           </tr>
           <!--Begin Navigational Buttons-->
           <tr>
             <td rowspan="5" align="left" valign="top">
               <IBA:Categories id="Categories" runat="server"/>
             </td>
             <td valign="top">
               <center>
								<br>
								<input type="hidden" value="/IBuyAdventure/default.aspx" id="ReturnUrl" runat="server">
								<P><font size="2">要购买本站物品 请先登陆或注册:<br><br>
								<table cellpadding="5" colspan="2">
									<tr>
										<td width="310" bgcolor="#800000">
											<font color="#ffffff" style="Verdana, Arial, Helvetica" size="2"><b>注册</b></font>
										</td>
									</tr>
									<tr>
										<td bgcolor="f7efde" valign=top>
											<table>
												<tr>
													<td width=100><font size="2">用户名: </font></td>
													<td><asp:textbox id="UserName" width="160" runat="server"/></td>