I am trying to add code behind file for .aspx file of sharepoint site pages. I followed the instructions given on this link Here

But I am getting this error

Could not load the assembly 'CustomPage, Version=, Culture=neutral, PublicKeyToken=d8b1948ab52231c9'. Make sure that it is compiled before accessing the page

I have installed the .dll file in GAC. I have typed the above assembly details using gacutil.

The page directive looks as follows :

    <%@ Assembly Name="Microsoft.SharePoint, Version=, Culture=neutral, PublicKeyToken=71e9bce111e9429c"%> 
<%@ Page MasterPageFile="~masterurl/default.master" 
Language="C#" Inherits="CustomPage.CustomFile, CustomPage, Version=, Culture=neutral, PublicKeyToken=d8b1948ab52231c9" %>
 <%@ Import Namespace="Microsoft.SharePoint.WebPartPages" %> <%@ 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" %> <%@ Import Namespace="Microsoft.SharePoint" %> <%@ Assembly Name="Microsoft.Web.CommandUI, Version=, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>
<%@ Register Tagprefix="WebPartPages" Namespace="Microsoft.SharePoint.WebPartPages" Assembly="Microsoft.SharePoint, Version=, Culture=neutral, PublicKeyToken=71e9bce111e9429c" %>

And I am not able to find any error in my .aspx page too. Is the error because of some safe controls of sharepoint.

Update: found the culprit. The code-behind file was initally compiled against the .Net 4.5 framework; once compiled against the 3.5 version (SP 2010 requires that), everything started to work.

1 Answer 1


The assembly declaration seems wrong. Report here the Page directive, so we can see what's wrong.

Anyway, it should resemble this:

Inherits="AssemblyNameSpace.CustomPageClassName, AssemblyNameSpace,Version=,..."
  • I have updated my question @MdMazzotti
    – A Beginner
    Apr 22, 2015 at 9:12
  • @ABeginner try adding this: <%@ Assembly Name="CustomPage.CustomFile, CustomPage, Version=, Culture=neutral, PublicKeyToken=d8b1948ab52231c9" %>
    – MdMazzotti
    Apr 22, 2015 at 9:16
  • I got this error on adding the assembly directive : The given assembly name or codebase was invalid. (Exception from HRESULT: 0x80131047)
    – A Beginner
    Apr 22, 2015 at 9:24
  • @ABeginner Are you sure you compiled it targeting the .NET 3.5 framework version?
    – MdMazzotti
    Apr 22, 2015 at 9:26
  • No, I compiled it in .net framework 4.5 @MdMazzotti
    – A Beginner
    Apr 22, 2015 at 9:28

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