How do I send messages from server to client using

I am just starting to explore signalR and I would like to able to send messages from the server to all clients.

Here is my Hub

 using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using SignalR;
using SignalR.Hubs;
using SignalR.Hosting.Common;
using SignalR.Hosting.AspNet;
using System.Threading.Tasks;

namespace MvcApplication1
{
    public class Chat : Hub
    {
        public void Send(String message)
        {
            // Call the addMessage methods on all clients
            Clients.addMessage(message);
        }
    }
}

Here is my client Page

      <script type="text/javascript">

         $(function () {

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

             // Declare a function on the chat hub so the server can invoke it
             chat.addMessage = function (message) {
                 $("#messages").append("<li>" + message + "</li>");
             };

             $("#broadcast").click(function () {
                 // call the chat method on the server
                 chat.send($("#msg").val());
             });

             $.connection.hub.start();
         });
    </script>


}



<input type="text" id="msg" />
        <input type="button" id="broadcast" value="broadcast" />

        <ul id="messages" class="round">


        </ul>

This all works perfectly, I am able to "chat" between 2 different browsers.

The next thing I want to do is initiate a message from the server to all clients.

So I tried this.

 using SignalR;
using System.Web.Http;
using System.Web.Mvc;
using System.Web.Optimization;
using System.Web.Routing;
using System;
using System.Web.Routing;
using SignalR;
using SignalR.Hubs;

namespace MvcApplication1
{
    // Note: For instructions on enabling IIS6 or IIS7 classic mode, 
    // visit http://go.microsoft.com/?LinkId=9394801

    public class MvcApplication : System.Web.HttpApplication
    {
        protected void Application_Start()
        {            
            var aTimer = new System.Timers.Timer(1000);

            aTimer.Elapsed += aTimer_Elapsed;
            aTimer.Interval = 3000;
            aTimer.Enabled = true;

            AreaRegistration.RegisterAllAreas();

            WebApiConfig.Register(GlobalConfiguration.Configuration);
            FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
            RouteConfig.RegisterRoutes(RouteTable.Routes);
            BundleConfig.RegisterBundles(BundleTable.Bundles);
            AuthConfig.RegisterAuth();
        }

        void aTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
        {
            var context = GlobalHost.ConnectionManager.GetHubContext<Chat>();
            context.Clients.Send("Hello");      
        }
    }
}

This doesn't seem to work. The Timer works, The "aTimer_Elapsed" event handeler runs every 3 seconds but the "Send" method on the chat hub is never run.

Any ideas?

回答1:

I think it should be

 void aTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
    {
        var context = GlobalHost.ConnectionManager.GetHubContext<Chat>();
        context.Clients.All.addMessage("Hello");      
    }

instead. With Send you are calling the method used by the client to call the server...

回答2:

Yes you must set that line to:

void aTimer_Elapsed(object sender, System.Timers.ElapsedEventArgs e)
    {
        var context = GlobalHost.ConnectionManager.GetHubContext<Chat>();
        context.Clients.All.addMessage("Hello");      
    }

However this is only half way and still wont work.

In your Js you need to write:

$(function () {

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

// Declare a function on the chat hub so the server can invoke it
chat.client.addMessage = function (message) {
    $("#messages").append("<li>" + message + "</li>");
};

$("#broadcast").click(function () {
    // call the chat method on the server
    chat.client.addMessage($("#msg").val());
});

$.connection.hub.start();
});

I added the chat.clientthis will add a client-side hub method that the server will call.