SqlDependency not working mvc app. Hits once - asp.net-mvc

Question

I am following the blog http://www.venkatbaggu.com/signalr-database-update-notifications-asp-net-mvc-usiing-sql-dependency/ to get a signalR push message out to connected clients.
My debugger never hits the onchange event.
my Global.asax.cs:
string connString = ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;
protected void Application_Start()
{
// basic stuff
SqlDependency.Start(connString);
var repo = new Repositories.MarkerRepository();
repo.GetAllMarkers(); // to register the dependency
}
My MarkerRepository.cs:
readonly string _connString = ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;
private MarkersHub _mh = new MarkersHub(); // my signalr hub class
public IEnumerable<House> GetAllMarkers()
{
var markers = new List<House>();
using (var connection = new SqlConnection(_connString))
{
connection.Open();
using (var command = new SqlCommand(#"SELECT * FROM [dbo].Houses", connection))
{
command.Notification = null;
var dependency = new SqlDependency(command);
dependency.OnChange += new OnChangeEventHandler(dependency_OnChange);
if (connection.State == ConnectionState.Closed)
connection.Open();
var reader = command.ExecuteReader();
while (reader.Read())
{
markers.Add(item: new House {
ID = (int)reader["ID"],
Name = (string)reader["Name"],
Code = reader["Code"] != DBNull.Value ? (string)reader["Code"] : "",
Latitude = Convert.ToDouble(reader["Latitude"]),
Longitude = Convert.ToDouble(reader["Longitude"])
});
}
}
}
return markers;
}
private void dependency_OnChange(object sender, SqlNotificationEventArgs e)
{
if (e.Type == SqlNotificationType.Change)
{
_mh.SendMarkers();
}
}
I have had a hit once but it was no change, only a notification for subscribe. I have read a lot about resubscribe, but when it hit this event the sql:
select * from sys.dm_qn_subscriptions
still returns no rows. Not on my db or master. So I think that there is an error in the blog post with the re-subscribe to the on change event? This sample https://msdn.microsoft.com/en-us/library/a52dhwx7(VS.80).aspx does unregister in the onchange event and calls the method which registers a new event. Can someone verify my assumption?

Answer 1

These were the values for the SqlNotificationEventArgs e in my event and told me that my query to depend on, was invalid.
SqlNotificationEventArgs.Type --> SqlNotificationType.Subscribe
SqlNotificationEventArgs.Info --> SqlNotificationInfo.Invalid
SqlNotificationEventArgs.Source --> SqlNotificationSource.Statement
The statement may not use the asterisk () or table_name. syntax to specify columns.
source https://msdn.microsoft.com/en-us/library/ms181122.aspx