Aspnetcore: AmbiguousMatchException using MapAreaRoute with ASP.NET Core 2.2

[Rick-Anderson]

Using the following routes:

app.UseMvc(routes =>
{
    routes.MapAreaRoute(
        name: "MyAreaProducts",
        areaName:"Products",
        template: "Products/{controller=Home}/{action=Index}/{id?}"
        );
    routes.MapAreaRoute(
        name: "MyAreaServices",
        areaName: "Services",
        template: "Services/{controller=Home}/{action=Index}/{id?}"
        );
    routes.MapRoute(
       name: "default",
       template: "{controller=Home}/{action=Index}/{id?}");
});

Navigation to https://localhost:5001/Products/Home/About throws:

An unhandled exception occurred while processing the request.
AmbiguousMatchException: The request matched multiple endpoints. Matches:

MVCareas.Areas.Products.Controllers.HomeController.About (MVCareas)
MVCareas.Controllers.HomeController.About (MVCareas)
Microsoft.AspNetCore.Routing.Matching.DefaultEndpointSelector.ReportAmbiguity(CandidateSet candidates)

Repo here: Run app and select the Products/Home/About link.

Work around is to disable endpoint routing:

public void ConfigureServices(IServiceCollection services)
{
    services.AddMvc(options =>
           options.EnableEndpointRouting = false)
           .SetCompatibilityVersion(CompatibilityVersion.Version_2_2);
}

Using .NET Core 2.2.2

dotnet --version
2.2.104

cc @JamesNK

[JamesNK]

Thanks for logging this.

The issues is already fixed in 3.0. To be decided whether to patch in 2.2. Most likely not because there is a simple work-around in 2.2.

[mgolois]

@JamesNK, @mkArtakMSFT did this fix made it to .net core 2.2.3, which has just been released?

[JamesNK]

It didn't. For 2.2 you should disable endpoint routing. In 3.0 this is fixed.

[VaibhavSharma1981]

You need to add area descriptor to controller to make it run. Ex.[Area("Admin")]

[binraider]

I had this problem in Core 3.0. I finally found the solution was to put a route attribute on the action - e.g. [Route("NodeInfo")]. That fixed it

[alizorlu]

Yeap. I just had same problem.
Solution is Route Attribute
Example ;

before class

[Route("areaName/[controller]")]
public class MyController:ControllerBase{}