如何实现SignalR显示电子邮件通知收件人在ASP.NET MVC 4应用程序

我需要使用SignalR向接收者显示电子邮件通知。我正在使用MVC 4开发我的应用程序。我是一个初学者，对SignalR了解不多。到目前为止，我已经按照下面的帖子，并试图准备一个样本，可以满足我的要求。

http://www.codeproject.com/Articles/732190/Real-Time-Web-Solution-for-Chat-by-MVC-SignalR-H

http://techbrij.com/realtime-post-comment-notifications-signalr-knockout

上面一个是使用knockout.js，另一个不是。我都照做了，但还是不能满足我的要求。

下面是SignalR Hub类的代码:

  public void SendEmail(Email email)
        {
            email.SentBy = WebSecurity.CurrentUserId;
            using (NotifyEntities db = new NotifyEntities())
            {
                UsersContext uc = new UsersContext();
                db.Emails.Add(email);
                db.SaveChanges();
                var ret = new
                {
                    Message = post.Message,
                    SentBy = post.SentBy,
                };
                Clients.Caller.sendEmail(ret);

                #region add to table which contain user id and email_post_id (I am sending the email to 2 users/receivers)
                UsersMessage msgRel = new UsersMessage();
                msgRel.EID = email.Id;
                msgRel.UID = 2; //user 1
                db.UsersMessages.Add(msgRel);
                db.SaveChanges();

                msgRel = new UsersMessage();
                msgRel.EID = email.Id;
                msgRel.UID = 5;//user 2
                db.UsersMessages.Add(msgRel);
                db.SaveChanges();
                #endregion

                var unread = (from ure in db.Emails.ToList()
                              join um in db.UsersMessages on ure.Id equals um.EID
                              where um.UID == WebSecurity.CurrentUserId && um.IsReaded == false
                              orderby ure.Id descending
                              select new
                              {
                                  Message = pst.Message,
                                  SentBy = pst.SentBy,
                              }).ToArray();

                Clients.All.loadUnreadPosts(unread); //this returns unread emails of currently logged in user
                Clients.All.loadPosts(ret); // this returns all emails of currently logged in user
            }
        }

当我不使用knockout.js时，我无法显示即时通知，它只出现在页面刷新时，它显示给所有用户，而不是接收器。

当我使用knockout.js时，通知立即显示，但同样的问题存在，消息/通知显示给所有用户。

请帮我一下。我不知道如何为特定邮件的收件人创建组

public async Task UserOnline(string emailAddress)
{
    await Groups.Add(this.Context.ConnectionId, emailAddress);
}

Clients.Group(emailAddress).loadUnreadPosts(unread); 
Clients.Group(emailAddress).loadPosts(ret);