Error when using CreatedAtRoute in ASP.NET Core minimal API

Question

I'm trying to use CreatedAtRoute in minimal API.

app.MapGet("/clients/{id:int}", [EndpointName("GetClientById")] async (int id, ClientsContext db) =>
  await db.Clients.SingleOrDefaultAsync(client => client.Id == id));

app.MapPost("/clients", async (ClientsContext db, Client client) =>
{
  var newClient = db.Add(client);
  await db.SaveChangesAsync();
  var entity = newClient.Entity;
  var url = $"{host}/clients/{newClient.Entity.Id}";
  return Results.CreatedAtRoute(
    routeName:   "GetClientById",
    routeValues: new { id = entity.Id  },
    value:       entity);
});

I use EndpointName attribute to name the endpoint I refer to in POST request. However, I get the exception:

System.InvalidOperationException: No route matches the supplied values.

This is strange since there's only one parameter in url pattern - id.

A little note

You can use WithName instead of [EndpointName] attribute:

app
  .MapGet("/clients-m/{id:int}", async (int id, ClientsContext db) =>
    await db.ClientsM.SingleOrDefaultAsync(client => client.Id == id))
  .WithName("GetClientByIdAsync");

Answer 1

For minimal APIs, try using .WithName instead for setting the EndpointNameAttribute i.e.

app.MapGet("/clients/{id:int}", async (int id, ClientsContext db) =>
  await db.Clients.SingleOrDefaultAsync(client => client.Id == id))
.WithName("GetClientById");