SignalR Notifications not show when add new row to table

Please developers help me a week ago I could not solve the problem

These is details of project as :

1- Startup.cs file as :

[assembly: OwinStartupAttribute(typeof(LinkForEmployment.Startup))]
[assembly: OwinStartup(typeof(LinkForEmployment.Startup))]
namespace LinkForEmployment
{
public partial class Startup
{
public void Configuration(IAppBuilder app)
{
app.MapSignalR();
ConfigureAuth(app);
}
}
}

2- NotificationHub.cs file as :

using Microsoft.AspNet.SignalR;
namespace LinkForEmployment
{
public class NotificationHub : Hub
{
//public void Hello()
//{
// Clients.All.hello();
//}
}
}

3- NotificationComponent.cs file as :

using Microsoft.AspNet.SignalR;
using System;
using System.Collections.Generic;
using System.Configuration;
using System.Data.SqlClient;
using System.Linq;
using LinkForEmployment.Models;
using System.Web;
namespace LinkForEmployment
{
public class NotificationComponent
{
//Here we will add a function for register notification (will add sql dependency)
public void RegisterNotification(DateTime currentTime)
{
string conStr = ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;
string sqlCommand = @"SELECT [UserId],[NotificationTitle],[NotificationIcon],[NotificationMessage],[link],[NotificationTime] from [dbo].[Notifications] where [NotificationTime] > @AddedOn";
//you can notice here I have added table name like this [dbo].[Contacts] with [dbo], its mendatory when you use Sql Dependency
using (SqlConnection con = new SqlConnection(conStr))
{
SqlCommand cmd = new SqlCommand(sqlCommand, con);
cmd.Parameters.AddWithValue("@AddedOn", currentTime);
if (con.State != System.Data.ConnectionState.Open)
{
con.Open();
}
cmd.Notification = null;
SqlDependency sqlDep = new SqlDependency(cmd);
sqlDep.OnChange += sqlDep_OnChange;
//we must have to execute the command here
using (SqlDataReader reader = cmd.ExecuteReader())
{
// nothing need to add here now
}
}
}
void sqlDep_OnChange(object sender, SqlNotificationEventArgs e)
{
//or you can also check => if (e.Info == SqlNotificationInfo.Insert) , if you want notification only for inserted record
if (e.Type == SqlNotificationType.Change)
{
SqlDependency sqlDep = sender as SqlDependency;
sqlDep.OnChange -= sqlDep_OnChange;
//from here we will send notification message to client
var notificationHub = GlobalHost.ConnectionManager.GetHubContext();
notificationHub.Clients.All.notify("added");
//re-register notification
RegisterNotification(DateTime.Now);
}
}
public List GetData(DateTime afterDate)
{
using (ApplicationDbContext db = new ApplicationDbContext())
{
return db.Notifications.Where(a => a.NotificationTime > afterDate).OrderByDescending(a => a.NotificationTime).ToList();
}
}
}
}

4-Global.asax.cs file as :

namespace LinkForEmployment
{
public class MvcApplication : System.Web.HttpApplication
{
string con = ConfigurationManager.ConnectionStrings["DefaultConnection"].ConnectionString;
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
RouteConfig.RegisterRoutes(RouteTable.Routes);
GlobalConfiguration.Configure(WebApiConfig.Register);
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
BundleConfig.RegisterBundles(BundleTable.Bundles);
SqlDependency.Start(con);
}
protected void Session_Start(object sender, EventArgs e)
{
NotificationComponent NC = new NotificationComponent();
var currentTime = DateTime.Now;
HttpContext.Current.Session["LastUpdated"] = currentTime;
NC.RegisterNotification(currentTime);
}
protected void Application_End()
{
//here we will stop Sql Dependency
SqlDependency.Stop(con);
}
}
}

5- model class file is as :

public class Notification
{
public int Id { get; set; }
public string UserId { get; set; }
public string NotificationTitle { get; set; }
public string NotificationIcon{ get; set; }
public string NotificationMessage { get; set; }
public string link { get; set; }
public DateTime NotificationTime { get; set; }
}

6- NotificationController file is as :

public class NotificationController : Controller
{
public JsonResult GetNotifications()
{
var notificationRegisterTime = Session["LastUpdated"] != null ? Convert.ToDateTime(Session["LastUpdated"]) : DateTime.Now;
NotificationComponent NC = new NotificationComponent();
var list = NC.GetData(notificationRegisterTime);
//update session here for get only new added contacts (notification)
Session["LastUpdate"] = DateTime.Now;
return new JsonResult { Data = list, JsonRequestBehavior = JsonRequestBehavior.AllowGet };
}
}

7- _Layout.cshtml Shared page as :

@using LinkForEmployment.Models;
@using Microsoft.AspNet.Identity;
"en-US">
"utf-8" />
"viewport" content="width=device-width, initial-scale=1.0">
@*@Styles.Render("~/Content/css")*@
"~/Content/bootstrap.css" rel="stylesheet" />
"~/Content/bootstrap-rtl.min.css" rel="stylesheet" />
"stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css" />
"~/Content/style.css" rel="stylesheet" />
"~/Scripts/modernizr-2.6.2.js">
@Html.Partial("_EmployerNavbar")
class="container-fluid pageContent myContainer" id="cont">
class="row">
@RenderBody()

class="page-footer">

@*@Scripts.Render("~/bundles/jquery")*@

"~/Scripts/jquery-1.10.2.min.js">

"~/Scripts/jquery.signalR-2.2.0.min.js">

"/signalr/hubs">

"~/Scripts/bootstrap.min.js">

@*@Scripts.Render("~/bundles/bootstrap")*@

@* @RenderSection("scripts", required: false)*@

"text/css">

/*Added css for design notification area, you can design by your self*/

/* COPY css content from youtube video description*/

.noti-content {

position: fixed;

right: 100px;

background: yellow;

color: blue;

font-size: medium;

font-style: oblique;

font-family: Arial;

border-radius: 4px;

top: 47px;

width: 440px;

display: none;

border: 1px solid #9E988B;

}

ul#notiContent {

max-height: 200px;

overflow: auto;

padding: 0px;

margin: 0px;

padding-left: 20px;

}

ul#notiContent li {

margin: 3px;

padding: 6px;

background: #FF6600;

}

.noti-top-arrow {

border-color: transparent;

border-bottom-color: #F5DEB3;

border-style: dashed dashed solid;

border-width: 0 8.5px 8.5px;

position: absolute;

right: 32px;

top: -8px;

}

span.noti {

color: lightgreen;

margin: 15px;

position: fixed;

right: 100px;

font-size: 30px;

cursor: pointer;

}

span.count {

position: fixed;

top: -1px;

/*color:white;*/

}

/*.noti:hover {

color:white;

}*/

@* Add jquery code for Get Notification & setup signalr *@

"text/javascript">

$(function () {

// Click on notification icon for show notification

$('span.noti').click(function (e) {

debugger;

e.stopPropagation();

$('span.noti').css("color", "lightgreen");

$('span.count').hide();

$('.noti-content').show();

var count = 0;

count = parseInt($('span.count').html()) || 0;

count++;

// only load notification if not already loaded

if (count > 0) {

updateNotification();

}

$('span.count', this).html(' ');

})

// hide notifications

$('html').click(function () {

$('.noti-content').hide();

})

// update notification

function updateNotification() {

$('#notiContent').empty();

$('#notiContent').append($('

'));

$.ajax({

type: 'GET',

url: '/Notification/GetNotifications',

success: function (response) {

debugger;

$('#notiContent').empty();

if (response.length == 0) {

$('#notiContent').append($('

Currently You Have No New Notifications.

'));

}

$.each(response, function (index, value) {

$('#notiContent').append($('

The User , ' + value.NotificationTitle + ' ' + 'Of ID' + ' (' + value.NotificationMessage + ') Is Written Something.

'));

});

error: function (error) {

console.log(error);

}

})

}

// update notification count

function updateNotificationCount() {

$('span.count').show();

var count = 0;

count = parseInt($('span.count').html()) || 0;

count++;

$('span.noti').css("color", "white");

$('span.count').css({ "background-color": "red", "color": "white" });

$('span.count').html(count);

}

// signalr js code for start hub and send receive notification

var notificationHub = $.connection.notificationHub;

$.connection.hub.start().done(function () {

console.log('Notification hub started');

});

//signalr method for push server message to client

notificationHub.client.notify = function (message) {

if (message && message.toLowerCase() == "added") {

updateNotificationCount();

}

})

"~/Scripts/Style.js">

"~/Scripts/OurJQuery.js">

6 Replies

Know the answer? Post it — somebody with the same question will find it here.

kumar vipin6y ago
Firstly Check the hubs are started or not console.log('Notification hub started'
); this will show you
if it is started then the message is not getting supplied in application
notificationHub.client.notify = function (message) {
if (message && message.toLowerCase() == "added") {
updateNotificationCount();
}
}
In that Case firstly check signalr is working or not
Askmejust Portal6y ago
Sir,
In my case notification data are fetched very well but notification counting are not showing in the span count, i mean there are not update the number of notification.
Kindly suggest me how to solve this problem.
kumar vipin6y ago
Firstly check that sql dependency is working Properly or not by putting a breakpoint on dependecy handler method

Must Consider that query you have written should affect to take signalr in effect
Check magical script of signalr is there or not after running app put url localhost/Signalr/Hubs
try removing where [NotificationTime] > @AddedOn
Ultimate Programmer7y ago
Does Sql (on change)Notification support in .Net Core?, Did you fix this issue, I am trying the same. Got the same result as yours. Please let me know. Thank you
Abdulmajeed Alshari8y ago
Thank sir Altaf Ansari
Are you can explain where can i write calling code for written function in hub class in my codes pleas because I did not understand it well yet
Can you type the call code for a function named hubFunction for example
Altaf Ansari8y ago
Hello Abdalmajeed Alshari,

You need to create function inside the hub class if you want to call a function through signalr..
first create a test function inside hub class and try to call this function.. check in debugging mode its calling hub calss function or not.. if its calling this that function that means your signalr process working fine.. then add your function in hub class then try the same..

for more please check..

http://www.c-sharpcorner.com/article/signalr-chat-app-with-asp-net-webform-and-bootstrap/