System.web.Mvc version conflict in instance & code

Question

I have a fresh instance with v10.1.2, which has System.Web.Mvc 5.2.4 In my Visual Studio solution, I have projects with .Net 4.8 which has System.Web.Mvc 5.2.9.
When I publish the code into the instance, it is only the custom dlls and pdb files. They do not include System.Web.Mvc.

But still, the CMS doesn't load and throws an error saying, cannot find the System.Web.Mvc version.

To handle this, I have downgraded Microsoft.AspNet.Mvc to 5.2.4. The issue is now resolved.

But for each project and all the new projects, this step needs to be done. If I include System.Web.Mvc (5.2.9) in publish, then the web.config of the instance for all environments (DEV,UAT, PRD) have to be updated.

What is the better way to handle this?

Answer 1

There are two options available to you.

The first and the recommended approach is to do as you have done and downgrade the reference in your visual studio solution to match what is running in the sitecore instance. This will ensure that the sitecore DLLs are running against what was intended and fully tested.

The second approach would be to add a binding redirect to the Web config file. This would look similar to the below:

<dependentAssembly>
  <assemblyIdentity name="System.Web.Mvc" publicKeyToken="31bf3856ad364e35" />
  <bindingRedirect oldVersion="5.2.4.0-5.2.9.0" newVersion="5.2.4.0" />
</dependentAssembly>

This will ensure any previous references, baked into your custom DLL will be redirected to the version that exists in the bin folder.

Answer 2

When I publish the code into the instance, it is only the custom DLLs and PDB files. They do not include System.Web.Mvc.

-This is because your project is referred to the DLL(System.Web.Mvc 5.2.9) available in project references.

To handle this, I have downgraded Microsoft.AspNet.Mvc to 5.2.4. The issue is now resolved.

-If you are using any other third-party NuGet packages/DLLs and there are dependencies with the latest MVC DLLs then you must have to refer the latest DLLs and assembly binding needs to be updated in the root web.config.