How to resolve Method not found: 'System.Collections.Generic.IList`1<Microsoft.Extensions.FileProviders.IFileProvider> In .Net Core 3.1

Question

I am facing below issue while migrating .Net Core 2.2 MVC project to 3.1 .

Method not found: 'System.Collections.Generic.IList`1<Microsoft.Extensions.FileProviders.IFileProvider> Microsoft.AspNetCore.Mvc.Razor.RazorViewEngineOptions.get_FileProviders()'.

Any Suggestions are welcome.

Below is the sample Code.

1. ConfigureServices Method.

   services.Configure<MvcRazorRuntimeCompilationOptions>(options =>
   {
       options.FileProviders.Clear();
       options.FileProviders.Add(new EmbeddedFileProvider(typeof(HomeController).GetType().Assembly));
   });
   services.AddControllersWithViews().AddRazorRuntimeCompilation();
   

2. Configure Method.

   app.UseRouting();
   
   app.UseEndpoints(endpoints =>
   {
       // Mapping of endpoints goes here:
       endpoints.MapControllerRoute("default", "{controller=Home}/{action=Index}/{id?}");         
   });
   

3. Controller.

   public class HomeController : Controller
   {
       public IActionResult Index()
       {
           return View();
       }
   }
   

Let me know If further details are required.

Answer 1

You need the Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation NuGet package and these usings:

using System.Reflection;
using Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation;
using Microsoft.Extensions.FileProviders;

You can also have the code something like this for ex:

public void ConfigureServices(IServiceCollection services)
{
    services.Configure<Microsoft.AspNetCore.Mvc.Razor.RuntimeCompilation.MvcRazorRuntimeCompilationOptions>(options =>
    {
        options.FileProviders.Add(
        new EmbeddedFileProvider(typeof(HomeController).GetTypeInfo().Assembly));
    });
    
    // Requires using System.Reflection;
    var assembly = typeof(HomeController).GetTypeInfo().Assembly;
    services.AddMvc().AddRazorRuntimeCompilation()
                    .AddApplicationPart(assembly)
                    .SetCompatibilityVersion(CompatibilityVersion.Version_3_0);
}