vs2010 MasterPage 创建控件时出错
有人可以解释这个错误吗？
创建控件时出错 - 头 你调用的对象是空的。
<%@ Page Title="" Language="C#" MasterPageFile="~/Controls/Master1.Master"
AutoEventWireup="true" CodeBehind="GrupoUsuario.aspx.cs" Inherits="GrupoUsuario" %>
<asp:Content ID="Content1" runat="server" contentplaceholderid="head">
</asp:Content>
我认为这是 Visual Studio 2010 在设计视图中的一个错误。我没有使用任何事件来操作 OnInt() 方法中的会话对象。 “PlaceHolderTopo”是 Web 用户控件 Topo.ascx 中的占位符。工作正常啊我在从母版页继承的页面的内容占位符内没有任何代码并收到此错误。
下面是母版页的代码：
<%@ Master Language="C#" AutoEventWireup="true" CodeBehind="PrincipalSeguranca.Master.cs" Inherits="PrincipalSeguranca" %>
<%@ Register Src="Topo.ascx" TagName="Topo" TagPrefix="uc1" %>
<%@ Register src="MenuAdmin.ascx" TagName="MenuAdmin" TagPrefix="uc2" %>
<%@ Register src="Rodape.ascx" tagname="Rodape" tagprefix="uc3" %>
<!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>Sistema</title>
<script language="jscript" type="text/javascript" src="Scripts/Geral.js"></script>
<link rel="shortcut icon" href="../layout/ico/favicon.ico" type="image/x-icon" />
<link rel="stylesheet" href="../layout/css/styles.css" type="text/css" />
<link href="../layout/css/menu_tabbed.css" rel="stylesheet" type="text/css" />
<link rel="stylesheet" href="../layout/css/contents.css" type="text/css" />
</head>
<body>
<form id="form1" ClientInstanceName="form1" runat="server">
<uc1:Topo ID="Topo1" runat="server" />
<div id="corpo">
<asp:ContentPlaceHolder ID="head" runat="server">
</asp:ContentPlaceHolder>
</div>
<div id="rodape">
<uc3:Rodape ID="Rodape1" runat="server" />
</div>
</form>
</body>
</html>
Someone can explain this error?
Error Creating Control - head
Object reference not set to an instance of an object.
<%@ Page Title="" Language="C#" MasterPageFile="~/Controls/Master1.Master"
AutoEventWireup="true" CodeBehind="GrupoUsuario.aspx.cs" Inherits="GrupoUsuario" %>
<asp:Content ID="Content1" runat="server" contentplaceholderid="head">
</asp:Content>
I Think this is a bug of visual studio 2010 in design view. I'not using any event to manipulate session object in the method OnInt(). The "PlaceHolderTopo" is an placeholder in the web user control Topo.ascx. It's work normaly. I Don't have any code inside the content place holder in the page tha inherits from the master page and get this error.
Below is the code of the masterpage:
<%@ Master Language="C#" AutoEventWireup="true" CodeBehind="PrincipalSeguranca.Master.cs" Inherits="PrincipalSeguranca" %>
<%@ Register Src="Topo.ascx" TagName="Topo" TagPrefix="uc1" %>
<%@ Register src="MenuAdmin.ascx" TagName="MenuAdmin" TagPrefix="uc2" %>
<%@ Register src="Rodape.ascx" tagname="Rodape" tagprefix="uc3" %>
<!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>Sistema</title>
<script language="jscript" type="text/javascript" src="Scripts/Geral.js"></script>
<link rel="shortcut icon" href="../layout/ico/favicon.ico" type="image/x-icon" />
<link rel="stylesheet" href="../layout/css/styles.css" type="text/css" />
<link href="../layout/css/menu_tabbed.css" rel="stylesheet" type="text/css" />
<link rel="stylesheet" href="../layout/css/contents.css" type="text/css" />
</head>
<body>
<form id="form1" ClientInstanceName="form1" runat="server">
<uc1:Topo ID="Topo1" runat="server" />
<div id="corpo">
<asp:ContentPlaceHolder ID="head" runat="server">
</asp:ContentPlaceHolder>
</div>
<div id="rodape">
<uc3:Rodape ID="Rodape1" runat="server" />
</div>
</form>
</body>
</html>
如果你对这篇内容有疑问，欢迎到本站社区发帖提问 参与讨论，获取更多帮助，或者扫码二维码加入 Web 技术交流群。
绑定邮箱获取回复消息
由于您还没有绑定你的真实邮箱，如果其他用户或者作者回复了您的评论，将不能在第一时间通知您！
发布评论
评论（1）
您的
Rodape控件在设计时存在错误。当您在设计视图中打开页面时，它会在 Visual Studio 的进程中创建自定义控件的实例。由于您的网站实际上并未运行，因此您控件中的代码可能正在访问某些尚未初始化的静态成员。
您应该启动 Visual Studio 的第二个副本，将其调试器附加到第一个副本，从“调试”菜单中设置“在所有异常上中断”，然后找到您的错误。
You have a bug in your
Rodapecontrol at design time.When you open your page in Design view, it creates an instance of your custom control in Visual Studio's process. Since your website is not actually running, the code in your control is probably accessing some static member which hasn't been initialized.
You should launch a second copy of Visual Studio, attach its debugger to the first copy, set Break on All Exceptions from the Debug menu, and find your bug.