The HealthServiceActionPage gives you a very nice mechanism by which you can declaratively define pages handling various HealthVault shell targets. However, folks frequently run in to situation where they need more dynamic way of redirecting and handling shell targets. A simple scenario is if you want to users to come back to the same URL they clicked after being authorized by healthvault shell, e.g. User clicks and returns to https://www.healthapp.com/username/stats instead of going to the default home https://www.healthapp.com/username/.

Here is a code snippet which illustrates how to extend the HealthServiceActionPage:

    using System;
    public partial class Redirect : Microsoft.Health.Web.HealthServiceActionPage
    {
        //We don't want this page to require log on because when we sign out,
        //we still want this page to read the WCPage_ActionSignOut key in the
        protected override bool LogOnRequired
        {
            get
            {
                return false;
            }
        }
    
        public const String ActionQueryStringValue = "actionqs";
        public const String DefaultURL = "http://www.healthapp.com/username";
    
        protected override void OnActionApplicationAuthorizationSuccessful(string action, 
         string actionQueryString)
        {
            string targetLocation;
            String fullTargetLocation;
            string url = Request.QueryString[ActionQueryStringValue];
            // TODO: Validate that the URL is from home domain
            if (url != null)
            {
                targetLocation = url;
            }
            else
            {
                targetLocation = DefaultURL;
            }
            // we assume that the query string startswith '?'
            fullTargetLocation = targetLocation + actionQueryString;
            Response.Redirect(fullTargetLocation);
        }
    }

The magic is in the OnActionApplicationAuthorizationSuccessful method, which allows us to override the authorization successful target. The HealthVault SDK HealthServiceActionPage now provides us several OnAction methods which could be use to override the particular APPAUTH targets.

You can also download this code from MSDN Code here.