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我正在尝试返回用户表并将其显示在使用母版页的页面上。所谓AjaxMaster.Master当我尝试抓取GridView以显示数据时，GridView返回null
我的母版页文件看起来像这样 -
<%@ Master Language="C#" AutoEventWireup="true" CodeBehind="AjaxMaster.master.cs"
Inherits="e.AjaxMaster" %>
<!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 id="AjaxHead1" runat="server">
<title></title>
<link rel="stylesheet" type="text/css" href="Global.css" />
<style type="text/css">
#backtoblog a
{
position: absolute;
top: 7px;
left: 15px;
text-decoration: none;
}
</style>
<asp:ContentPlaceHolder ID="ajaxhead" runat="server">
</asp:ContentPlaceHolder>
</head>
<body>
<form id="ajaxform1" runat="server">
<asp:ToolkitScriptManager ID="AjaxToolkitScriptManager2" runat="server" />
<div>
</div>
<asp:LoginView ID="AjaxLoginView1" runat="server">
<LoggedInTemplate>
<div id="companyLogo">
<img src="images/company_logo.png" alt="Company Logo" border="0" width="123" border="0"
height="40" />
</div>
<div id="header">
<!-- start of main -->
<div id="welcome">
<a href="Welcome.aspx">Welcome</a> <strong>
<asp:LoginName ID="LoginName1" runat="server" />
</strong>, [
<asp:LoginStatus ID="LoginStatus1" runat="server" LogoutAction="RedirectToLoginPage" />
]
</div>
<span id='sm_holder'></span>
<div class="clear">
</div>
<%
string sPagePath = System.Web.HttpContext.Current.Request.Url.AbsolutePath;
System.IO.FileInfo oFileInfo = new System.IO.FileInfo(sPagePath);
string sPageName = oFileInfo.Name;
%>
<div>
<!-- start of TabContainer -->
<asp:TabContainer ID="TabContainer1" runat="server" ActiveTabIndex="1">
<asp:TabPanel runat="server" HeaderText="Home" ID="TabPanel1">
<HeaderTemplate>
<span>
<img src="iconimages/home001.png" alt="Home" border="0" height="10px" /> Home</span>
</HeaderTemplate>
<ContentTemplate>
<!-- Start of Home -->
<% Response.WriteFile("HomeTab.aspx"); %>
<!-- End of Home -->
</ContentTemplate>
</asp:TabPanel>
<asp:TabPanel runat="server" HeaderText="Dashboard" ID="TabPanel7">
<HeaderTemplate>
<p>
Dashboard</p>
</HeaderTemplate>
<ContentTemplate>
<!-- Start of Dashboard -->
<% Response.WriteFile("DashboardTab.aspx"); %>
<!-- End of Dashboard -->
</ContentTemplate>
</asp:TabPanel>
<asp:TabPanel ID="TabPanel2" runat="server" HeaderText="Locations">
<HeaderTemplate>
<p>
Locations</p>
</HeaderTemplate>
<ContentTemplate>
<!-- Start of Locations -->
<% Response.WriteFile("LocationsTab.aspx"); %>
<!-- End of Locations -->
</ContentTemplate>
</asp:TabPanel>
<asp:TabPanel ID="TabPanel3" runat="server" HeaderText="Users">
<HeaderTemplate>
<p>
Users</p>
</HeaderTemplate>
<ContentTemplate>
<!-- Start of Users -->
<asp:SqlDataSource ID="SqlDataSource1" runat="server" ConnectionString="<%$ ConnectionStrings: SiteSQL %>"
SelectCommand="SELECT * FROM aspnet_Users"></asp:SqlDataSource>
<asp:GridView ID="GridView1" runat="server">
</asp:GridView>
<!-- End of Users -->
</ContentTemplate>
</asp:TabPanel>
<asp:TabPanel ID="TabPanel4" runat="server" HeaderText="Reports">
<HeaderTemplate>
<p>
Reports</p>
</HeaderTemplate>
<ContentTemplate>
<!-- Start of Reports -->
<% Response.WriteFile("ReportsTab.aspx"); %>
<!-- End of Reports -->
</ContentTemplate>
</asp:TabPanel>
<asp:TabPanel ID="TabPanel5" runat="server" HeaderText="Alerts">
<HeaderTemplate>
<p>
Alerts</p>
</HeaderTemplate>
<ContentTemplate>
</ContentTemplate>
</asp:TabPanel>
<asp:TabPanel ID="TabPanel6" runat="server" HeaderText="Preferences">
<HeaderTemplate>
<p>
Preferences</p>
</HeaderTemplate>
<ContentTemplate>
<!-- Start of Preferences -->
<!-- start of left Panel for Preferences -->
<%-- <div id="leftColumn">--%>
<%-- </div>--%>
<!-- end of left Panel for Preferences -->
<!-- End of Preferences -->
</ContentTemplate>
</asp:TabPanel>
</asp:TabContainer>
<!-- end of TabContainer -->
<div class="clear">
</div>
<div class="line">
</div>
<div>
<asp:ContentPlaceHolder ID="ContentPlaceHolder1" runat="server">
</asp:ContentPlaceHolder>
</div>
<div id="footer">
</div>
</LoggedInTemplate>
<AnonymousTemplate>
You are not logged in.
<br />
Please login to access eservice
</AnonymousTemplate>
</asp:LoginView>
</form>
</body>
</html>
和代码隐藏文件看起来像这样 -
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.SqlClient;
namespace e
{
public partial class AjaxMaster : System.Web.UI.MasterPage
{
protected void Page_Load(object sender, EventArgs e)
{
if (!IsPostBack)
{
BindUsersGrid();
}
}
private void BindUsersGrid()
{
SqlConnection conn;
SqlCommand comm;
SqlDataReader reader;
string connectionString = System.Configuration.ConfigurationManager.ConnectionStrings["SiteSQL"].ConnectionString;
conn = new SqlConnection(connectionString);
comm = new SqlCommand("SELECT * FROM aspnet_Users", conn);
try
{
conn.Open();
reader = comm.ExecuteReader();
GridView gridviewusers = (GridView)AjaxLoginView1.FindControl("GridView1");
gridviewusers.DataSource = reader;
gridviewusers.DataBind();
reader.Close();
}
finally
{
conn.Close();
}
}
}
}
它编译好的，但是当我运行它，该行 -
GridView gridviewusers = (GridView)AjaxLoginView1.FindControl("GridView1");
返回空，下面的行会引发异常 -
gridviewusers.DataSource = reader;
gridviewusers.DataBind();
异常的堆栈跟踪是这样的 -
Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.
Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.
Source Error:
An unhandled exception was generated during the execution of the current web request. Information regarding the origin and location of the exception can be identified using the exception stack trace below.
Stack Trace:
[NullReferenceException: Object reference not set to an instance of an object.]
eservice.AjaxMaster.BindUsersGrid() in AjaxMaster.Master.cs:115
eservice.AjaxMaster.Page_Load(Object sender, EventArgs e) in AjaxMaster.Master.cs:27
System.Web.Util.CalliHelper.EventArgFunctionCaller(IntPtr fp, Object o, Object t, EventArgs e) +14
System.Web.Util.CalliEventHandlerDelegateProxy.Callback(Object sender, EventArgs e) +35
System.Web.UI.Control.OnLoad(EventArgs e) +99
System.Web.UI.Control.LoadRecursive() +50
System.Web.UI.Control.LoadRecursive() +141
System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +627
Version Information: Microsoft .NET Framework Version:2.0.50727.3603; ASP.NET Version:2.0.50727.3614
线115 AjaxMaster.Master.cs的是 -
gridviewusers.DataSource = reader;
哪里是AjaxLoginView1在你的页面的标记？ – 2010-07-13 00:11:53