Question

我想通过线程发送通知。我创建了一个迭代自我无限时间的线程。这是我的代码。

    public static class ThreadStartUp
{
    public static void GetThread()
    {
        var thread = new Thread(ReminderHelperClas.IterateMethod);
        thread.Start();
    }

}

MY Static class with methods is

    public static class ReminderHelperClas
{
    public static void CheckReminder()
    {
        try
        {
            const string usernamesendby = "38";
            const string message = "Please give feedback to assigned task.";
            var chathub = new ChatHub();
            using (var db = new DatabaseContext())
            {
                var datetimenow = DateTime.Now;
                const TaskAssignStatus recordstatus = (TaskAssignStatus)3;

                var remindermodel =
                    db.ActionTaskVarainceCategories.Where(x => x.TaskAssignStatus != recordstatus)
                        .Select(x => x)
                        .ToList();

                foreach (var item in remindermodel)
                {
                    if (item.ToDate == datetimenow || item.ToDate < datetimenow)
                    {
                        var username = db.Users.Where(u => u.ID == item.AssignedToID).Select(u => u.UserName).FirstOrDefault();

                        var msgclass = new TaskMessagingModel { FromId = 38, Message = message, UserName = username, ToId = item.AssignedToID };
                        SaveMessages.TaskSaveMessage(msgclass);
                        chathub.Send(usernamesendby, message, username);
                    }
                }
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }

    public static void IterateMethod()
    {
        try
        {
            while (true)
            {
                CheckReminder();
                Thread.Sleep(10000);
            }
        }
        catch (Exception ex)
        {
            throw ex;
        }
    }
}

当保存消息时，我调用了发送通知方法，但它给了我null异常，虽然我提供了所有参数。请帮我这个。

Answer 1

您无法初始化集线器类并调用其方法。要使集线器调用方法，您应该使用 GlobalHost.ConnectionManager.GetHubContext（）传入要获取其对象的集线器类。例如

private readonly IHubContext _chatHub = GlobalHost.ConnectionManager.GetHubContext<ChatHub>();

然后，您现在可以使用聊天中心上下文并调用要发送提醒的组或 Clients 属性中的方法，以便

_chatHub.Clients.Client(clientConnectionString)
                        .Send(usernamesendby, message, username);

有关详情，建议您查看本教程http://www.asp.net/signalr/overview/getting-started/tutorial-server-broadcast-with-signalr

修改 clientConnectionString 是您要将消息发送到的特定客户端的 connectionId 。所以问题是你是否将消息发送给特定的客户？如果是特定客户端，则必须覆盖 ChatHub 中的 OnConnected（）方法，并在内存中获取并保留connectionId或在数据库中，然后在CheckReminder方法中，您现在将访问connectionId并使用它将消息发送给特定用户。你可以这样做。

public override Task OnConnected() { string connectionId = Context.ConnectionId; IPrincipal user = Context.User; //Save connection. _clientManager.AddToCorrectGroup(user, connectionId; return base.OnConnected(); }

我想通过signalR使用线程发送通知

1 个答案: