public static async void AddTask(string description)
        {
            if (App.CurrentUserID != -1)
            {
                DateTime currentTime = DateTime.Now;
                // 上传一个起止时间相同的时间记录,表明有这个任务
                TomatoTime time = new TomatoTime()
                {
                    BeginTime     = currentTime.ToString("yyyy-MM-dd HH:mm:ss"),
                    EndTime       = currentTime.ToString("yyyy-MM-dd HH:mm:ss"),
                    UserId        = App.StaticUser.UserId,
                    Description   = description,
                    BeginTimeDate = currentTime.Date.ToShortDateString(),
                    SpanString    = currentTime.ToShortTimeString() + " → " + currentTime.ToShortTimeString()
                };
                await App.TomatoTimeManager.AddTomatoTimeTaskAsync(time);

                await App.UserManager.ModifyUserTaskAsync(App.StaticUser);
            }

            TomatoTask tomatoTask = new TomatoTask();

            tomatoTask.TaskName    = description;
            tomatoTask.TimeRecords = new List <TomatoTime>();
            tomatoTask.TotalTimes  = new TimeSpan();
            tasks.Insert(0, tomatoTask);
            RecordCountChanged();
        }
        public static void RefreshUserTasks()
        {
            var records = App.TomatoTimeManager.UserTomatoTimes;

            tasks.Clear();
            foreach (var task in records)
            {
                TomatoTask tomatoTask = new TomatoTask();
                tomatoTask.TaskName    = task.Key;
                tomatoTask.TimeRecords = task.Value;
                tomatoTask.TotalTimes  = new TimeSpan();
                // 去掉占位的时间记录
                for (int i = task.Value.Count - 1; i >= 0; i--)
                {
                    var record = task.Value[i];
                    if (record.BeginTime == record.EndTime)
                    {
                        tomatoTask.TimeRecords.Remove(record);
                        break;
                    }
                }
                foreach (var record in task.Value)
                {
                    tomatoTask.TotalTimes += Convert.ToDateTime(record.EndTime) - Convert.ToDateTime(record.BeginTime);
                }
                tasks.Add(tomatoTask);
            }
            RecordCountChanged();
        }
 public static void DeleteTask(TomatoTask task)
 {
     tasks.Remove(task);
     RecordCountChanged();
 }