为什么我这个跨网页传递一直报错!未将对象实例化??
第一个页面
<tr><td>用户名:</td><td class="style1">
<asp:TextBox ID="TextBox1" runat="server" Width="272px" Font-Size="Large"></asp:TextBox>
</td>
<td><asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ControlToValidate="TextBox1"
ErrorMessage="用户姓名不能为空" Font-Size="Medium" ForeColor="red"></asp:RequiredFieldValidator></td>
</tr>
<tr><td><asp:Button ID="Button1" runat="server" Text="提交" PostBackUrl="~/Default3.aspx" onclick="Button1_Click" /></td></tr>
第二页面CS
public partial class Default3 : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (PreviousPage.IsCrossPagePostBack == true)
{
TextBox TextBox1 = (TextBox)PreviousPage.FindControl("TextBox1");
Username.Text += "用户名:" + TextBox1.Text;
}
}
}
前台
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default3.aspx.cs" Inherits="Default3" %>
<%@ PreviousPageType VirtualPath="~/Default2.aspx" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
<caption><font style="display:block; text-align:center" color="DodgerBlue" size="6" face="微软雅黑">信息预览页面</font></caption>
<table class="tb">
<tr> <td> <asp:Label ID="Username" runat="server" Font-Size="Large"></asp:Label></td></tr>
</div>
</form>
</body>
</html>