Getting the host of the current site on ASP.NET

Normally this isn't a problem because you are working with a request which contains the host name of the current server.  I had a unique problem where I was starting some threads from the Global.asax application objects and some of those threads would generate emails that contain click-back links to the site. 

#1. I added a public variable to my Global object 

public class Global : System.Web.HttpApplication
{
   private string _ServerRoot = string.Empty;
   public string ServerRoot
   {
      get { return _ServerRoot; } 
   }

#2. I added code to the Application_start the filled in _ServerRoot

void Application_Start(object sender, EventArgs e)
{
   // create the server root
   Uri uriMap = new Uri(Context.Request.Url.AbsoluteUri);
   StringBuilder bldNow = new StringBuilder();
   bldNow.Append(uriMap.Scheme);
   bldNow.Append("://");
   bldNow.Append(uriMap.Host);
   if (uriMap.Port != 80)
   {
      bldNow.Append(":");
      bldNow.Append(uriMap.Port);
   }
   _ServerRoot = bldNow.ToString();

#3. I passed the object to my threaded object.  I chose this way so I didn't have to worry about context when I need to get the address.

void Application_Start(object sender, EventArgs e)

{

   ... other init code

   // start threads

   Friend.Current.Init(this);

#4. I save the class in my threaded object

      
public void Init(Global global)
{
   try
   {
      CurrentApplication = global;
      Init(SystemName, null);



Anytime I need to get access to the server address I just reference CurrentApplication.ServerRoot from inside my thread.

I'm looking for something cleaner, let me know if you've come up with something.