/// <summary>
        /// 添加or修改内容
        /// </summary>
        /// <returns></returns>
        private async Task AddOrModifyToDo()
        {
            try
            {
                if (EditedToDo != null)
                {
                    if (_addMode == AddMode.None)
                    {
                        return;
                    }

                    if (string.IsNullOrEmpty(EditedToDo.Content))
                    {
                        await ToastService.SendToastAsync(ResourcesHelper.GetResString("ContentEmpty"));

                        return;
                    }

                    ShowPaneOpen = false;

                    //显示进度条
                    IsLoading = Visibility.Visible;

                    //添加
                    if (_addMode == AddMode.Add)
                    {
                        await AddOrRestoreAndSyncNewToDo();
                    }
                    //修改
                    else if (_addMode == AddMode.Modify)
                    {
                        await ModifyAndSyncToDo();
                    }
                }
            }
            catch (Exception ex)
            {
                var task = ExceptionHelper.WriteRecordAsync(ex, nameof(MainViewModel), nameof(AddOrModifyToDo));
            }
        }
        /// <summary>
        /// 修改待办事项
        /// </summary>
        /// <returns></returns>
        private async Task ModifyAndSyncToDo()
        {
            IsLoading = Visibility.Visible;

            //修改当前列表
            var itemToModify = AllToDos.ToList().Find(sche =>
            {
                if (sche.ID == EditedToDo.ID)
                {
                    return(true);
                }
                else
                {
                    return(false);
                }
            });

            itemToModify.Content    = EditedToDo.Content;
            itemToModify.Category   = CateVM.Categories[AddingCate].CateColorID;
            itemToModify.CreateTime = DateTime.Now.ToString();

            UpdateDisplayList(CateVM.Categories[SelectedCate].CateColorID);

            //离线模式
            if (App.IsInOfflineMode)
            {
                await SerializerHelper.SerializerToJson <ObservableCollection <ToDo> >(AllToDos, SerializerFileNames.ToDoFileName);

                EditedToDo = new ToDo();

                Messenger.Default.Send(new GenericMessage <ObservableCollection <ToDo> >(AllToDos), MessengerTokens.UpdateTile);

                return;
            }
            //非离线模式
            else if (App.CanSendRequest)
            {
                try
                {
                    var resultUpdate = await CloudService.UpdateContent(itemToModify.ID, itemToModify.Content, itemToModify.CreateTime, itemToModify.Category);

                    if (resultUpdate)
                    {
                        AllToDos.ToList().Find(sche =>
                        {
                            if (sche.ID == EditedToDo.ID)
                            {
                                return(true);
                            }
                            else
                            {
                                return(false);
                            }
                        }).Content = EditedToDo.Content;

                        EditedToDo = new ToDo();

                        Messenger.Default.Send(new GenericMessage <ObservableCollection <ToDo> >(AllToDos), MessengerTokens.UpdateTile);
                    }
                }
                catch (COMException)
                {
                    await ToastService.SendToastAsync(ResourcesHelper.GetResString("RequestError"));
                }
            }
            IsLoading = Visibility.Collapsed;
        }