public MResultModel ChangeClassRank(ChangeClassRankModel inputM)
        {
            MResultModel resM;

            try
            {
                _classListBLL.ChangeClassRank(inputM.ClassID, inputM.TargetClassID);
                resM = MResultModel.GetSuccessResultM("调换成功");
            }
            catch (ArgumentNullException ex)
            {
                resM = MResultModel.GetFailResultM(ex.Message);
            }
            catch (ArgumentException ex)
            {
                resM = MResultModel.GetFailResultM(ex.Message);
            }
            return(resM);
        }