.net – aspnet_compiler finding wrong version of System.Web.WebPages 1.0.0.0 instead of 2.0.0.0

.netasp.netasp.net-mvc-4

I have an ASP.NET MVC4 project which compiles fine in VS2010. For deployment purposes I run a Nant script which attempts to precompile the website using aspnet_compiler.exe but I keep running into an assembly reference issue with System.Web.WebPage

error CS1705: Assembly 'System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' uses 'System.Web.WebPages, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' which has a higher version than referenced assembly 'System.Web.WebPages, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35'

I also have the following assembly bindings in my web.config:

<runtime>
    <assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
        <dependentAssembly>
            <assemblyIdentity name="System.Web.Helpers" publicKeyToken="31bf3856ad364e35" />
            <bindingRedirect oldVersion="1.0.0.0-2.0.0.0" newVersion="2.0.0.0" />
        </dependentAssembly>
        <dependentAssembly>
            <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
            <bindingRedirect oldVersion="0.0.0.0-4.0.0.0" newVersion="4.0.0.0" />
        </dependentAssembly>
        <dependentAssembly>
            <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" />
            <bindingRedirect oldVersion="0.0.0.0-2.0.0.0" newVersion="2.0.0.0" />
        </dependentAssembly>
        <dependentAssembly>
            <assemblyIdentity name="System.Web.WebPages.Razor" publicKeyToken="31bf3856ad364e35" />
            <bindingRedirect oldVersion="0.0.0.0-2.0.0.0" newVersion="2.0.0.0" />
        </dependentAssembly>
    </assemblyBinding>
</runtime>

and my csproj has the following reference:

<Reference Include="System.Web.WebPages, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35">
  <Private>True</Private>
 <HintPath>..\packages\AspNetWebPages.Core.2.0.20126.16343\lib\net40\System.Web.WebPages.dll</HintPath>
</Reference>

Best Solution

I solved this problem by explicitly referencing the 2.0 assembly in Web.config. I suppose that for some reason, the ASP.NET compiler (in my case when running MvcBuildViews), uses the old 1.0 assembly first, if it is found.

<?xml version="1.0" encoding="utf-8"?>
<configuration>
  <!-- … -->
  <system.web>
    <!-- … -->
    <compilation debug="true" targetFramework="4.0">
      <assemblies>
        <add assembly="System.Web.Mvc, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL" />
        <add assembly="System.Web.Abstractions, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
        <add assembly="System.Web.Routing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
        <add assembly="System.Web.WebPages, Version=2.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35, processorArchitecture=MSIL" />
      </assemblies>
    </compilation>
    <!-- … -->
  </system.web>
  <!-- … -->
</configuration>

BTW: It looked like this problem occurred for the first time after I added a 3rd party ASP.NET MVC 3.0 component. That component works fine through the assembly binding, but it may be the reason why the ASP.NET compiler tries to load the 1.0 web pages first.