引发异常时更改HTTP状态代码

Question

I use custom class which derive from HandleErrorAttribute to handle exeptions When in my MVC application user requested content, which is not allowed to him I throw AuthenticationException and I want to change HTTP status code to 401.

public class HandleErrorFilterAttribute : HandleErrorAttribute
{
    public override void OnException(ExceptionContext filterContext)
    {
        if (typeof(AuthenticationException) == filterContext.Exception.GetType())
        {
            filterContext.HttpContext.Response.StatusCode = 401;
        }
    }
}

But my result is status code 500, when I debugging I enter in this code, in Application_Error(object, EventArgs) status is changed to 401, but finally MVC override my settings.
How to change response HTTP status? What I do wrong?

Answer 1

filterContext is passed by value. That's means that it creates copy of object that was passed as argument of function and you changed value of copy.

In common, you need to use ref keyword to pass argument by reference, so you'll have same instance of ExceptionContext as was passed;

In case of override you can't change function arguments. So you need to rethink your program architecture.