SqlDep_OnChange with SignalR does not work

Follow the code below:

NotificationHub: Hub

private readonly static ConnectionMapping<string> _connections = new ConnectionMapping<string>();

public void SendNotification(string who)
{
    foreach (var connectionId in _connections.GetConnections(who))
    {
        var result = Clients.Client(connectionId);

        Clients.Client(connectionId).addNotification(who);
    }
}

Components.cs:

void SqlDep_OnChange(object sender, SqlNotificationEventArgs e)
{

    //from here we will send notification message to client
    NotificationHub notHub = new NotificationHub();
    notHub.SendNotification(Who);

    //...
}

_Layout:

$(function () {
    var connection = $.connection.notificationHub;

    //signalr method for push server message to client
    connection.client.addNotification = function (who) {
        //send notification here
        console.info("Send Notification")
    };

    // Start hub
    $.connection.hub.start().done(function () {
        console.log("SignalR Started")
    });
});

In class Hub and line var result = Clients.Client(connectionId); is returning some fields as null.

Image: link

The following code works with the click function of jquery:

 $(function () {
        var connection = $.connection.notificationHub;

        //signalr method for push server message to client
        connection.client.addNotification = function (who) {
            //send notification here
            console.info("Send Notification")
        };

        // Start hub
        $.connection.hub.start().done(function () {
            $("#testeclick").click(function () {
                connection.server.sendNotification("User15248");
            });
            console.log("SignalR Started")
        });
    });

Follow the result after the jQuery% function: link

The click function works perfectly. I just can not make it work with click when doing database change.

The idea is: After doing an "update" in the database, show a notification for client with signalr.

Any solution?

UPDATE: (Nearly solved problem)

NotificationHub: Hub

public static void SendNotification(string who)
        {
            IHubContext context = GlobalHost.ConnectionManager.GetHubContext<NotificationHub>();
            foreach (var connectionId in _connections.GetConnections(who))
            {
                var result = context.Clients.Client(connectionId);
                if (result != null)
                {
                    result.addNotification(who);
                }
            }
        }

Components.cs:

void SqlDep_OnChange(object sender, SqlNotificationEventArgs e)
{

    //from here we will send notification message to client
    NotificationHub.SendNotification("User1586");
    //...
}

Problem almost solved, if it has 50 users, it sends the notification 50 times to user "User1586". If you have 1000 users, send notification 1000 times.

With this line problem: SqlDep_OnChange (passes multiple times)