public class ServerHub : Hub

    {

       public async Task<string> ALongTimeTask()

        {

            var p = new Progress<int>();

            p.ProgressChanged += (a, count) =>

            {

                Clients.Caller.progressChanged(count);

            };

            var ret = await DoLongTimeTask(p);

            return ret;

        }

        private async Task<string> DoLongTimeTask(IProgress<int> p)

        {

            for (int i = ; i < ; i++)

            {

                p.Report(i);

                await Task.Delay();

            }

            return "finish";

        }

    }

        var hubConnection = new HubConnection("http://abc.com/signalr");

        client = hubConnection.CreateHubProxy("ServerHub");

        client.On("progressChanged", (count) =>

        {

　　　　　　//display current count;

        });

  　　　 var t = await client.Invoke<string>("ALongTimeTask");

        MessageBox.Show(t);

       var chat = $.connection.serverHub;

        chat.client.progressChanged = function (count) {

                // display count

          };

        chat.server.aLongTimeTask().done(function (result) {

                // display result

         });