private async void AddActivity()
        {
            var activityEdit = ActivityViewModel.GetInstance();

            activityEdit.Detail         = "";
            activityEdit.StartDate      = DateTime.Today;
            activityEdit.EndDate        = DateTime.Today;
            activityEdit.ActivityId     = 0;
            activityEdit.EffortTime     = 0;
            activityEdit.EffortMin      = 1;
            activityEdit.ActivityTypeId = 0;
            activityEdit.Clasification  = 0;
            activityEdit.IsUpdating     = false;
            activityEdit.ProjectId      = 0;
            await activityEdit.LoadActivityProjects();

            await navigationService.Navigate("ActivityPage");
        }
        private async void SelectActivity()
        {
            var activityEdit = ActivityViewModel.GetInstance();

            activityEdit.ActivityId = this.ActivityId;
            activityEdit.Detail     = this.Detail;
            activityEdit.StartDate  = this.StartDate ?? DateTime.Today;
            activityEdit.EndDate    = this.EndDate ?? DateTime.Today;
            activityEdit.EffortTime = this.EffortTime ?? 0;
            var effort = activityEdit.EffortTime.ToString(CultureInfo.InvariantCulture).ToString().Split('.');

            activityEdit.EffortMin      = GetMinutes(effort);
            activityEdit.EffortTime     = int.Parse(effort[0]);
            activityEdit.ActivityTypeId = this.ActivityType.ActivityTypeId;
            activityEdit.Clasification  = this.ActivityClasification.ActivityClasificationId == Constant.Personal ? 0 : 1;
            activityEdit.IsUpdating     = true;
            activityEdit.ProjectId      = this.Project.ProjectId;
            await activityEdit.LoadActivityProjects();

            await navigationService.Navigate("ActivityPage");
        }