Razor 2 to Razor 3 MVC 5

Question

I've been working on an MVC 4 solution, and I've been trying to upgrade it to MVC 5. I've followed the steps outlined here.

I've followed it, and now whenever I run the MVC Application, it gives me this error message:

[A]System.Web.WebPages.Razor.Configuration.HostSection cannot be cast to 
[B]System.Web.WebPages.Razor.Configuration.HostSection. 

Type A originates from 
'System.Web.WebPages.Razor, Version=2.0.0.0, Culture=neutral, 
PublicKeyToken=31bf3856ad364e35' in the context 'Default' at location 
'C:\WINDOWS\Microsoft.Net\assembly\GAC_MSIL\System.Web.WebPages.Razor\v4.0_2.0.0.0__31bf3856ad364e35\System.Web.WebPages.Razor.dll'. 
Type B originates from 'System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, 
PublicKeyToken=31bf3856ad364e35' in the context 'Default' at location 
'C:\Users\User\AppData\Local\Temp\Temporary ASP.NET 
Files\root\665ac028\de53a189\assembly\dl3\c2c0a4b5\56e8099e_40e0ce01\System.Web.WebPages.Razor.dll'.

Does anyone know how this could have originated? or how it can be solved? I've looked around thus far? I've tried changing the web.config files, with no avail...

Answer 1

In your Web.config(-s) make sure assemblyBinding contains the proper version for the assembly System.Web.WebPages.Razor and System.Web.Mvc.

<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
  <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages.Razor" publicKeyToken="31bf3856ad364e35" />
        <bindingRedirect oldVersion="1.0.0.0-3.0.0.0" newVersion="3.0.0.0"/>
  </dependentAssembly>

  <dependentAssembly>
    <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
    <bindingRedirect oldVersion="1.0.0.0-5.0.0.0" newVersion="5.0.0.0" />
  </dependentAssembly>
</assemblyBinding>

And make sure that razor sectionGroup in ConfigSections reference latest versions as well:

<sectionGroup name="system.web.webPages.razor" type="System.Web.WebPages.Razor.Configuration.RazorWebSectionGroup, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35">
    <section name="host" type="System.Web.WebPages.Razor.Configuration.HostSection, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" />
    <section name="pages" type="System.Web.WebPages.Razor.Configuration.RazorPagesSection, System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="false" />
</sectionGroup>