<script type="text/javascript">

        $(function () {

            // Proxy created on the fly
            var job = $.connection.chatHub;

            // Declare a function on the job hub so the server can invoke it
            job.client.displayStatus = function () {
                getData();
            };

            // Start the connection
            $.connection.hub.start({ transport: 'longPolling' } );
            getData();
        });

        function getData() {
            var $tbl = $('#tbl');

            $.ajax({
                url: 'Chat.aspx/GetData',
                contentType: "application/json; charset=utf-8",
                dataType: "json",
                type: "POST",
                success: function (data) {
                    //debugger;
                    if (data.d.length > 0) {

                        newdata = data.d;
                        $tbl.empty();

                        var rows = [];

                        for (var i = 0; i < newdata.length; i++) {
                            
                                rows.push(' <tr><td>' + newdata[i].Id + '</td><td>' + newdata[i].Username + 
                                
                                $tbl.append(rows.join(''));
                        }
                    } 
                }   
             });
        }

    </script>

    <WebMethod>
    Public Shared Function GetData() As List(Of messaggi)

        Using connection = New SqlConnection(ConfigurationManager.ConnectionStrings("DatabaseSQL").ConnectionString)
            connection.Open()
            Dim lstRecords = New List(Of messaggi)()
            lstRecords.Clear()

            Using command As SqlCommand = New SqlCommand("select id, username, messaggio, tipomessaggio,inviaa from chat_1", connection)

                command.Notification = Nothing

                Dim dependency As SqlDependency = New SqlDependency(command)
                AddHandler dependency.OnChange, AddressOf Dependency_OnChange ' += new onchangeeventhandler(dependency_onchange)

                If connection.State = ConnectionState.Closed Then connection.Open()
                Using reader = command.ExecuteReader()
                    'lstRecords.ingresso =
                    lstRecords = reader.Cast(Of IDataRecord)().[Select](Function(x) New messaggi() With {.Id = x.GetInt32(0), .Username = x.GetString(1), .Messaggio = x.GetString(2), .TipoMessaggio = x.GetInt32(3), .InviaA = x.GetString(4)}).ToList()
                    Return lstRecords
                End Using
            End Using
        End Using

    End Function

    Private Shared Sub Dependency_OnChange(ByVal sender As Object, ByVal e As SqlNotificationEventArgs)
        'If (e.Type = SqlNotificationType.Change) Then
        ChatHub.Show()
        'End If
    End Sub

    Private Sub BtnInvia_Click(sender As Object, e As EventArgs) Handles BtnInvia.Click
        Dim client = New Net.WebClient()
        client.Headers.Add("apikey", ConfigurationManager.AppSettings("apikey"))
        Dim data = New NameValueCollection()
        Dim username As String = String.Empty
        If (Request.Cookies("UserSettings") IsNot Nothing) Then
            username = Request.Cookies("UserSettings")("Username")
        End If
        Dim InviaA As String = 0
        Dim TipoMessaggio As Integer = 1
        Dim testo As String = TxtMessaggio.Text

        ''SUSSURRO''
        Dim controlloStringa As Boolean = testo.Contains("@")
        If controlloStringa AndAlso (testo.IndexOf("@") = 0) Then
            Dim sussurro As String() = Split(testo, "@")
            If sussurro.Length = 3 Then
                InviaA = sussurro(1)
                testo = sussurro(2)
                TipoMessaggio = 2
            End If
        End If

        With data
            .Add("Username", username)
            .Add("Messaggio", testo)
            .Add("TipoMessaggio", TipoMessaggio)
            .Add("InviaA", InviaA)
        End With

        Dim result = client.UploadValues(ConfigurationManager.AppSettings("EndPointUrl") & "Chat/Inserisci", data)
        'Dim ObjectResult As ServicesResult.ObjectResult = Newtonsoft.Json.JsonConvert.DeserializeObject(Of ServicesResult.ObjectResult)(Encoding.ASCII.GetString(result))
        'If Not ObjectResult.ErrorResult Then
        '    Dim _result As List(Of Models.Missiva) = Newtonsoft.Json.JsonConvert.DeserializeObject(Of List(Of Models.Missiva))(ObjectResult.ValueResult.ToString)

        '    listaMissive.DataSource = _result
        '    listaMissive.DataBind()
        'Else
        '    Response.Write(ObjectResult.ErrorMessage)
        'End If
        TxtMessaggio.Text = ""
        TxtMessaggio.Focus()
    End Sub

<HubName("chatHub")>
Public Class ChatHub
    Inherits Hub

    Public Shared Sub Show()
        Dim context As IHubContext = GlobalHost.ConnectionManager.GetHubContext(Of ChatHub)()

        context.Clients.All.DisplayStatus()
    End Sub
End Class

public void SendMessage(string message)
{
  //Qui salvi il messaggio in SQL Server

  //e poi lo giri a tutti gli altri client
  this.Clients.AllExcept(this.Context.ConnectionId).newMessage(message);
}