集合根据属性分组获得多个集合进行操作

/// <summary>
        /// 刷新数据
        /// </summary>
        private void RefreshData()
        {
            //请求接口获取数据
            var res = Client.QueryListByObject<List<MdvcDeprPrdVo>>(ApiKey.ADMIN_PLATFORM_MDVCDEPRPRDHANDLER_GETALL, null);
            if (res.Flag == ResultFlag.SUCCESS)
            {
                List<MdvcDeprPrdVo> datas = res.Value ?? new List<MdvcDeprPrdVo>();
                datas = datas.OrderBy(m => m.DdpYear).ThenBy(n => n.DdpMonth).ToList();
                if (datas.Count > 0)
                {
                    //将集合根据属性进行分组获取多个集合
                    var gr = datas.GroupBy(m => m.DdpYear);
                    //对分组后获得的集合操作
                    foreach (var item in gr)
                    {
                        List<MdvcDeprPrdVo> mdpList = item.ToList();
                        if(mdpList!=null && mdpList.Count>0)
                        {
                            int i = 1;
                            foreach(var s in mdpList)
                            {
                                s.DdpYearMonth = $"{s.DdpYear}年第{i}期";
                                i++;
                            }
                        }
                    }
                }
                dgvMain.DataSource = datas;
            }
            else
            {
                MsgBox.Show($"接口报错！{res.Message}");
                Common.LocalLog.Write(Common.LogLevel.important, "{0}:{1},{2}", res + "失败", res.Flag.ToString(), res.Message);
            }
        }