路线开始处的可选参数

Question

I'm trying to create a route that satisfies below two scenarios:

1. en-us/mycontroller/action/1
2. mycontroller/action/1

Basically what I need is the below rule. But it seems that the system is always expecting the locale parameter, even though it's optional.

[Route("{locale?}/[controller]/[action]")]
public class MyController : Controller
{
     [Route("{id}")]
     public IActionResult Action(int id) {
          return View();
     }
}

Any idea how I can create a rule that supports above scenarios?

Answer 1

Optional parameters in routes must be at the end. There's no way around that. However, there's an alternate way to handle it: just add multiple routes:

[Route("{locale}/[controller]/[action]")]
[Route("[controller]/[action]")]

Now it will respond to either way. FWIW, you might want to consider adding some constraints to the locale param, though, so it doesn't match everything .