public static DataTable getFTList(this IEnumerable<UpfeleTablesMapping.fileType> enumer)
        {
            var datatable = new DataTable();
            foreach (PropertyDescriptor item in TypeDescriptor.GetProperties(typeof(UpfeleTablesMapping.fileType)))
            {
                datatable.Columns.Add(item.Name, item.PropertyType);
            }
                foreach (UpfeleTablesMapping.fileType ft in enumer)
                {
                    var row = datatable.NewRow();
                    foreach (PropertyDescriptor dp in TypeDescriptor.GetProperties(typeof(UpfeleTablesMapping.fileType)))
                    {
                        row[dp.Name] = dp.GetValue(ft);
                    }
                    datatable.Rows.Add(row);
                }

            return datatable;
        }

老是在row[dp.Name] = dp.GetValue(ft);报错了原因是DataSet 不支持 System.Nullable<>。求助博客朋友，以及it界人士 该如何解决