My application page code

<%@ Assembly Name="$SharePoint.Project.AssemblyFullName$" %>
<%@ Import Namespace="Microsoft.SharePoint.ApplicationPages" %>
<%@ Register Tagprefix="SharePoint" Namespace="Microsoft.SharePoint.WebControls" Assembly="Microsoft.SharePoint, Version=, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>
<%@ Register Tagprefix="Utilities" Namespace="Microsoft.SharePoint.Utilities" Assembly="Microsoft.SharePoint, Version=, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>
<%@ Register Tagprefix="asp" Namespace="System.Web.UI" Assembly="System.Web.Extensions, Version=, Culture=neutral, PublicKeyToken=31bf3856ad364e35" %>
<%@ Import Namespace="Microsoft.SharePoint" %>
<%@ Assembly Name="Microsoft.Web.CommandUI, Version=, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="CustomerCard.aspx.cs" Inherits="HnGTest.Pages.Pages.CustomerCard, $SharePoint.Project.AssemblyFullName$" MasterPageFile ="~masterurl/default.master" %>

while my code file structure

using System;
using Microsoft.SharePoint;
using Microsoft.SharePoint.WebControls;
using HnGTest.DataEntities;
using System.Configuration;
using System.Web.UI.WebControls;
using System.Web.UI;

namespace HnGTest.Pages.Pages
    public partial class CustomerCard : Microsoft.SharePoint.WebPartPages.WebPartPage 


<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
  <Module Name="Pages" Url="SitePages">
    <File Path="Pages\CustomerCard.aspx" Url="CustomerCard.aspx" Type="GhostableInLibrary"/>

Aspx and cs file within module that solution architexture structure like

enter image description here

but while I deploy I get an error:

"An unexpected error has occurred. "

Update : public partial class CustomerCard :

  • 1
    Can you please provide us with more details? Does the error occur when you deploy the WSP, or when you activate the feature? Do you have a message in the logs? An excerpt of the elements.xml file? Is the DLL correctly deployed to the GAC?
    – Evariste
    Dec 16, 2015 at 7:42
  • Feature activated successfully, but while open page from page library error throw and dll file is availabale in GAC folder @Evariste Dec 16, 2015 at 7:45
  • Thanks for these info. There must be a more detailed message: you can get it either from the ULS logs, or directly in the browser if you edit the web.config so it is displayed automatically (see for instance sharepoint.stackexchange.com/a/73798/35604)
    – Evariste
    Dec 16, 2015 at 7:51
  • In ULS log error "UserAgent not available, file operations may not be optimized." and all that web.config setting done as said @Evariste Dec 16, 2015 at 8:03
  • 1
    And no more explicit error in the browser? In the ULS logs you should also have Something more explicit... "UserAgent not available" is a generic error not directly related to your problem :(
    – Evariste
    Dec 16, 2015 at 8:10

1 Answer 1


After looking more carrefully at the code-behind, I noticed you inherit from LayoutsPageBase. However, your page is not an application page (inside _layouts), but a module (a file provisionned in a library).
I've never seen a module .aspx page inheriting from it, but always from Microsoft.SharePoint.WebPartPages.WebPartPage. That may be the problem.

  • I tried but not worked in my situation @Evariste Dec 16, 2015 at 8:09
  • I update code to class inherit from "Microsoft.SharePoint.WebPartPages.WebPartPage" but this try also failed :(..@Evariste Dec 17, 2015 at 6:18
  • We definitely need a more detailed error message, either by modifying the web.config or from the ULS logs...
    – Evariste
    Dec 17, 2015 at 6:35

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