Linq orderby 排序功能无效

            var Datas = from a in Ctx.TD_ProjInfos
                        join b in Ctx.TD_ProjManaFineRecds                            
                        on a.ProjID equals b.ProjID
                        orderby Convert.ToInt16(a.ProjID) descending
                        select new
                        {
                            a.ProjID,
                            a.ProjName,
                            a.CompanyName,
                            a.DomainName,
                            a.DepartmentName,
                            a.BranchName,
                            a.CustomerName,
                            a.DesignerName,
                            a.ProjManagerName,
                            a.SupervisionName,
                            a.EnginManagerName,
                            a.EnginAssistantName,
                            b.FineID,
                            b.FineType,
                            b.FinesDate,
                            b.RealTheAmountofPunishment,
                            b.FineReason,
                            b.ChargedState,
                            b.DebitDate,
                            b.BPMWorkFlowID
                        };
            var s = Search ?? new SearchCondition();
            if (!string.IsNullOrWhiteSpace(s.FinesDate_Start))
            {
                Datas = Datas.Where(i => Convert.ToDateTime(i.FinesDate) >= Convert.ToDateTime(s.FinesDate_Start));
            }
            if (!string.IsNullOrWhiteSpace(s.FinesDate_End))
            {
                Datas = Datas.Where(i => Convert.ToDateTime(i.FinesDate) <= Convert.ToDateTime(s.FinesDate_End));
            }
            Datas.OrderBy(i=>i.ProjID);
            return Datas;

 两个排序orderby，一个是查询的时候，一个是查询出来之后排序，都没效果
 求大神指教

Datas.OrderBy(i=>i.ProjID);
->
Datas = Datas.OrderBy(i=>i.ProjID);