ASP.NET母版页未加载

Question

I have a site that is giving me the following error:

Content controls are allowed only in content page that references a master page.

Here is the contents of the file it is trying to load:

<%@ Page Language="c#" MasterPageFile="~/shared/templates/Default.master" %>
<asp:Content ID="PageContent" runat="server" ContentPlaceHolderID="PageContentPlaceHolder" />

Default.master does exist in the location requested and does contain:

<asp:ContentPlaceHolder runat="Server" ID="PageContentPlaceHolder" />

Why is the child page not recognizing/loading the master page?

Thanks!

---

UPDATE - Here is the stack trace and .NET Version info:

[HttpException (0x80004005): Content controls are allowed only in content page that references a master page.]
   System.Web.UI.MasterPage.CreateMaster(TemplateControl owner, HttpContext context, VirtualPath masterPageFile, IDictionary contentTemplateCollection) +11119902
   System.Web.UI.Page.get_Master() +69
   System.Web.UI.Page.ApplyMasterPage() +18
   System.Web.UI.Page.PerformPreInit() +58
   System.Web.UI.Page.ProcessRequestMain(Boolean includeStagesBeforeAsyncPoint, Boolean includeStagesAfterAsyncPoint) +1256

Version Information: Microsoft .NET Framework Version:2.0.50727.5485; ASP.NET Version:2.0.50727.5483

Answer 1

母版页应与该页位于同一IIS应用程序中。

Answer 2

for the content page you have

<asp:Content ID="PageContent" runat="server" ContentPlaceHolderID="PageContentPlaceHolder" />

did you edited that or is it exact? maybe it needs a fully closed tag?

<asp:Content ID="PageContent" runat="server" ContentPlaceHolderID="PageContentPlaceHolder">
    content
</asp:Content>

Answer 3

Thanks everyone for your help, but in the end it turned out nobody would have been able to solve this with the information I provided. I did not write this code, but I'm stuck with maintaining it and this is the first I'd seen this site.

As it turns out, in the web.config, there was a class defined as a base type for all pages. This class was overwriting the MasterPageFile attribute based on the results of a database query which, in this case, was returning an empty result.

So, I'll post this as the answer here in case anyone is experiencing something that seems impossible - especially when maintaining legacy code. Check the web.config.