Could not load file or assembly 'System.Web.WebPages.Razor, Version=3.0.0.0

34
votes

I want using external logins so I installed Oauth by package manager:

 PM> Install-Package Microsoft.AspNet.WebPages.OAuth

Then I got this error after installed it then I install razor:

PM> Install-Package Microsoft.AspNet.Razor

But I still have this exception. Further more my application is an asp.net application and not a MVC application. Thanks for help.

[FileNotFoundException: Could not load file or assembly 'System.Web.WebPages.Razor, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.]
   Microsoft.Web.WebPages.OAuth.PreApplicationStartCode.Start() +0
5
c#asp.netrazor
When you say an aspp.net application; do you mean Webforms? Because MVC is still an asp.net application. As it goes; Razor is an MVC scripting language. If you are not building an MVC app; then it is no wonder you are having issues. Honestly; you answered the question yourself. – Dave Lawrence
Is your project based on .net4. Many component of Razor 3 maybe based on 4.5. Check my answer. – Anirudha Gupta

5 Answers

16
votes

Apologies in advance for this lo-tech suggestion, but another option, which finally worked for me after battling NuGet for several hours, is to re-create a new empty project, Web API in my case, and just copy the guts of your old, now-broken project into the new one. Took me about 15 minutes.

12
votes

You have upgraded to Razor 3. Remember that VS 12 (until update 4) doesn't support it. Install The Razor 3 from nuget or downgrade it through these step

geekswithblogs.net/anirugu/archive/2013/11/04/how-to-downgrade-razor-3-and-fix-the-issue-that.aspx

10
votes

Another option is to update the Microsoft.AspnNet.Mvc NuGet package. Be careful, because NuGet update does not update the Web.Config. You should update all previous version numbers to updated number. For example if you update from asp.net MVC 4.0.0.0 to 5.0.0.0, then this should be replaced in the Web.Config:

    <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>
  </configSections>

 <host factoryType="System.Web.Mvc.MvcWebRazorHostFactory, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />

<pages
    validateRequest="false"
    pageParserFilterType="System.Web.Mvc.ViewTypeParserFilter, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"
    pageBaseType="System.Web.Mvc.ViewPage, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35"
    userControlBaseType="System.Web.Mvc.ViewUserControl, System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35">
  <controls>
    <add assembly="System.Web.Mvc, Version=5.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" namespace="System.Web.Mvc" tagPrefix="mvc" />
  </controls>
</pages>
4
votes

Update using NuGet Package Manager Console in your Visual Studio

Update-Package -reinstall Microsoft.AspNet.Mvc
0
votes

What worked for me is: right click on project properties then Manage Nugget Packages then chose update tab then chose Microsoft.AspNet.Razor then downgrade to version 3.0.0