Convert nullable DateTime? to new format

LinqDateTimeConversion

public DataTable GetDelivery()
        {
            try
            {
                db_ProductionSystemEntities Context = this.GetContext();
                
                //var Records = Context.T_DELIVERY
                //                      .Include("T_CUST_INFO")
                //                      .Include("T_SHIPPING_COMPANY");

                var Records = (from delivery in Context.T_DELIVERY
                               join cust in Context.T_CUST_INFO on delivery.Cust_Digit equals cust.Cust_Digit
                               join ship in Context.T_SHIPPING_COMPANY on delivery.ShippingNo equals ship.ShippingNo
                               orderby cust.Cust_Digit, delivery.DeliveryNo, delivery.Deli_DueDate ascending
                               select
                               new
                               {
                                   _Cust_Digit = delivery.Cust_Digit,
                                   _Cust_Name = cust.Cust_Name,
                                   _DeliveryNo = delivery.DeliveryNo,
                                   _LotNumber = delivery.LotNumber,
                                   _Deli_DueDate = delivery.Deli_DueDate,
                                   _Deli_Description = delivery.Deli_Description,
                                   _ShippingNo = delivery.ShippingNo,
                                   _SpecialField1 = delivery.SpecialField1,
                                   _SpecialField2 = delivery.SpecialField2
                               }).AsEnumerable()
                              .Select(x => new {

                                  Cust_Digit = x._Cust_Digit, 
                                  Cust_Name = x._Cust_Name,
                                  DeliveryNo = x._DeliveryNo,
                                  LotNumber = x._LotNumber,
                                  Deli_DueDate = (x._Deli_DueDate ?? DateTime.MaxValue) == DateTime.MaxValue? "":(x._Deli_DueDate ?? DateTime.MaxValue).ToString("yyyy-mm-dd") ,
                                  Deli_Description = x._Deli_Description,
                                  ShippingNo = x._ShippingNo,
                                  SpecialField1 = x._SpecialField1,
                                  SpecialField2 = x._SpecialField2,
                              
                              });

                DataTable dt = EntityUtility.LINQToDataTable(Records);
                return dt;
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }