How to build an absolute URL for the host currently in use in an ASP.NET app
<p>I am currently in a dev only phase of development, and am using the VS built-in web server, configured for a fixed port number.  I am using the following code, in my <code>MembershipService</code> class, to build an email body with a confirmation link, but obviously this must change when I deploy to our prod host.</p>

<pre><code>var url = string.Format("http://localhost:59927/Account/CompleteRegistration/{0}", newMember.PendingReplyId);
</code></pre>

<p>How can I build this URL to always reflect the host that the code is running on, e.g. when deployed to prod the URL should be <code>http://our-live-domain.com/Account/..etc.</code></p>

<p><strong>MORE INFO</strong>:  This URL will is included in an email to a new user busy registering an account, so I cannot use a relative URL.</p>
