现在有一种更简便的方法:

There's an easier way to do this now:

    public MvcApplication()
    {
        var wrapper = new EventHandlerTaskAsyncHelper(DoAsyncWork);
        this.AddOnAuthenticateRequestAsync(wrapper.BeginEventHandler, wrapper.EndEventHandler);
    }

    private async Task DoAsyncWork(object sender, EventArgs e)
    {
        var app = (HttpApplication)sender;
        var ctx = app.Context;

        ...
        await doSomethingAsync();
    }

使用这种方法，您可以使用async关键字定义一个方法，并使用'EventHandlerTaskAsyncHelper'类包装该方法以生成BeginEventHandler和EndEventHandler方法，以传递给AddOnAuthenticateRequestAsync调用.

With this approach, you define a method using the async keyword and wrap that method using the 'EventHandlerTaskAsyncHelper' class to generate BeginEventHandler and EndEventHandler methods to pass into the AddOnAuthenticateRequestAsync call.