从 C# 异步方法返回多个值

Question

我分别使用过异步方法和返回多个值的方法。在这种特定情况下，“GetTaskTypeAndId()”方法应该是异步的，并且应该同时返回多个值。我应该如何使这个方法异步？

        public async Task DeleteSchoolTask(int schoolNumber, int taskDetailId)
        {  
            var result = GetTaskTypeAndId(taskDetailId); // This should be called asynchronously
            int taskId = result.Item1;
            string taskType = result.Item2;

            // step 1: delete attachment physically from server
            var fileService = new FileService(Logger, CurrentUser);
            var relativeFilePath = $"{schoolNumber}\\{Consts.RM_SCHOOL}\\{taskDetailId}";
            fileService.DeleteAttachmentFolderFromServer(Consts.CONFIG_SMP_UPLOADFILE_ROOTPATH, relativeFilePath);

            // step 2: delete records from database
            await _routineMaintenanceRepo.Value.DeleteSchoolTask(taskDetailId);
        }


        public (int, string) GetTaskTypeAndId(int taskDetailId) // How should I write this line using 'async Task'?
        {
            var detailRecord = await _routineMaintenanceRepo.Value.GetDetailRecord(taskDetailId);

            int taskId = 0;
            string taskType = "";

            switch (detailRecord.TaskType)
            {
                case 1:
                    taskId = (int)detailRecord.RoutineMaintenanceTaskId;
                    taskType = Consts.RM_DEFAULT;
                    break;
                case 2:
                    taskId = (int)detailRecord.RoutineMaintenanceTaskDuplicateId;
                    taskType = Consts.RM_DUPLICATE;
                    break;
                case 3:
                    taskId = (int)detailRecord.RoutineMaintenanceTaskSchoolId;
                    taskType = Consts.RM_SCHOOL;
                    break;
                default:
                    break;
            }
            return (taskId, taskType);
        }

Answer 1

在玩过代码之后，我能够弄清楚。这是解决方案。

        public async Task DeleteSchoolTask(int schoolNumber, int taskDetailId)
        {  
            var result = await GetTaskTypeAndId(taskDetailId);
            int taskId = result.Item1;
            string taskType = result.Item2;

            // step 1: delete attachment physically from server
            var fileService = new FileService(Logger, CurrentUser);
            var relativeFilePath = $"{schoolNumber}\\{Consts.RM_SCHOOL}\\{taskDetailId}";
            fileService.DeleteAttachmentFolderFromServer(Consts.CONFIG_SMP_UPLOADFILE_ROOTPATH, relativeFilePath);

            // step 2: delete records from database
            await _routineMaintenanceRepo.Value.DeleteSchoolTask(taskDetailId);
        }

        public async Task<(int, string)> GetTaskTypeAndId(int taskDetailId)
        {
            var detailRecord = await _routineMaintenanceRepo.Value.GetDetailRecord(taskDetailId);

            int taskId = 0;
            string taskType = "";

            switch (detailRecord.TaskType)
            {
                case 1:
                    taskId = (int)detailRecord.RoutineMaintenanceTaskId;
                    taskType = Consts.RM_DEFAULT;
                    break;
                case 2:
                    taskId = (int)detailRecord.RoutineMaintenanceTaskDuplicateId;
                    taskType = Consts.RM_DUPLICATE;
                    break;
                case 3:
                    taskId = (int)detailRecord.RoutineMaintenanceTaskSchoolId;
                    taskType = Consts.RM_SCHOOL;
                    break;
                default:
                    break;
            }
            return (taskId, taskType);
        }