WebBrowser detect a file download event

Question

I want to develop Internet explorer add-on. I need to detect when user download file, But I didn't find a relevant event for that. in this link there is a list of events, but there is no event for user that begin to download file

code example (took if from the link):

using mshtml;
using SHDocVw;

class EventHandlers
{
    public void OnBeforeNavigate2(object sender, ref object URL, 
                                  ref object Flags, ref object Target, 
                                  ref object PostData, ref object Headers, 
                                  ref bool Cancel) 
    {
        Console.WriteLine("BeforeNavigate2 fired!");
    }
}

class Program
{
    static void Main(string[] args)
    {
        EventHandlers e = new EventHandlers();
        SHDocVw.InternetExplorer IE = new SHDocVw.InternetExplorer();
        object Empty = 0;
        object URL = "http://www.live.com";

        // override BeforeNavigate2 event
        IE.BeforeNavigate2 += new
             SHDocVw.DWebBrowserEvents2_BeforeNavigate2EventHandler(
                     e.OnBeforeNavigate2);

        IE.Visible = true;
        IE.Navigate2(ref URL, ref Empty, ref Empty, ref Empty, ref Empty);

        System.Threading.Thread.Sleep(5000);

        IE.Quit();
    }
}