Web api中的请求始终为null？

Question

I have a Web API with a Base Controller, I wanna get requested controller name from Request.GetRouteData().Values["controller"] , as the following code :

public class BaseApiController : ApiController
{
    protected string EntityName;

    public BaseApiController()
    {
        //Request is null
        EntityName = Request.GetRouteData().Values["controller"] as string;
    }
}

But Request is always null in above code.
What's wrong with above code?

Answer 1

You just cannot use the Request property in the Controller 's c'tor. It gets called before the actual request is handed over to it by the framework.

Answer 2

This is expected - you're in the controllers constructor. The controller hasn't been initialized with the actual request yet. Try something like the following:

protected string EntityName 
{
  get { Request.GetRouteData().Values["controller"] as string; }
}

That should be accessible after the constructor has run, and when you're in a subclass method.

Answer 3

如果需要Headers，可以使用HttpContext.Current.Request.Headers