Could not load file or assembly 'System.Web.WebPages'

Question

I've had this problem before, but then all I needed to do was to clean and rebuild the project. Now that doesn't seem to work anymore. When I start my Asp.Net MVC3 project debugger, the site is opened in my browser. Instead of getting the first page presented in the browser, I get this error:

Parser Error Message: Could not load file or assembly 'System.Web.WebPages, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35' or one of its dependencies. The system cannot find the file specified.

Source Error: 
Line 31:         <add assembly="System.Web.Routing, Version=4.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
Line 32:         <add assembly="System.Web.Mvc, Version=3.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
Line 33:         <add assembly="System.Web.WebPages, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />
Line 34:       </assemblies>
Line 35:     </compilation>

I can't seem to figure out how to solve this. Any idea?

Answer 1

The solution for me was to go to my server and install the Web Pages Version 2 on the server.

Go to http://www.microsoft.com/en-us/download/details.aspx?id=34600

And download the package and run it.

It was as simple as that.

Answer 2

I had this problem. Maybe it occurred when I installed .NET MVC v4 over the top of MVC v3, not sure.

Anyway I removed the System.Web.WebPages reference from my project. Then in the Add Reference dialogue .NET tab there were two System.Web.WebPages references listed, a version 1.0.0.0 and a 2.0.0.0. I made sure to add the version 1.0.0.0 one as that was the one that was missing.

Answer 3

Worked for me:

1. Tools -> NuGet Package Manager -> Manage NuGet Packages for Solution

2. Browse

3. Search for "Microsoft.AspNet.WebPages"

4. Make sure all projects in solution have the latest version.

Answer 4

I scratched my head for a while over this problem when I had it. Eventually I noticed that I had the following section in the "runtime" section of my web.config.

<runtime>
 . . .
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-2.0.0.0" newVersion="2.0.0.0" />
      </dependentAssembly>
. . .
</runtime>

As you can see, this refers to version 2 of the assembly, which doesn't match the following code that you also have in the system.web/compilation/assemblies section of web.config.

<add assembly="System.Web.WebPages, Version=1.0.0.0, Culture=neutral, PublicKeyToken=31BF3856AD364E35" />

The actual assembly referenced in References for the project is indeed v1.0.0.0, so I changed the first chunk of code above to the following, which fixed the problem immediately. I'm not sure how the mistake got there in the first place.

<runtime>
 . . .
      <dependentAssembly>
        <assemblyIdentity name="System.Web.WebPages" publicKeyToken="31bf3856ad364e35" culture="neutral" />
        <bindingRedirect oldVersion="0.0.0.0-1.0.0.0" newVersion="1.0.0.0" />
      </dependentAssembly>
. . .
</runtime>