Using 'UseMvc' to configure MVC is not supported while using Endpoint Routing

Question

I had an Asp.Net core 2.2 project.

Recently, I changed the version from .net core 2.2 to .net core 3.0 Preview 8. After this change I see this warning message:

using 'UseMvc' to configure MVC is not supported while using Endpoint Routing. To continue using 'UseMvc', please set 'MvcOptions.EnableEndpointRouting = false' inside 'ConfigureServices'.

I understand that by setting EnableEndpointRouting to false I can solve the issue, but I need to know what is the proper way to solve it and why Endpoint Routing does not need UseMvc() function.

Answer 1

I found the solution, in the following official documentation "Migrate from ASP.NET Core 2.2 to 3.0":

There are 3 approaches:

1. Replace UseMvc or UseSignalR with UseEndpoints.

In my case, the result looked like that

  public class Startup
{

    public void ConfigureServices(IServiceCollection services)
    {
        //Old Way
        services.AddMvc();
        // New Ways
        //services.AddRazorPages();
    }


    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        app.UseStaticFiles();
        app.UseRouting();
        app.UseCors();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllerRoute("default", "{controller=Home}/{action=Index}");
        });

    }
}

OR
2. Use AddControllers() and UseEndpoints()

public class Startup
{

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddControllers();
    }


    public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
    {
        if (env.IsDevelopment())
        {
            app.UseDeveloperExceptionPage();
        }

        app.UseStaticFiles();
        app.UseRouting();
        app.UseCors();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
        });

    }
}

OR
3. Disable endpoint Routing. As the exception message suggests and as mentioned in the following section of documentation: use mvcwithout endpoint routing

services.AddMvc(options => options.EnableEndpointRouting = false);
//OR
services.AddControllers(options => options.EnableEndpointRouting = false);