EF实体查询出的数据List<T>转DataTable出现【DataSet 不支持 System.Nullable<>】的问题

　　　　 public static DataTable ToDataTable<T>(this IEnumerable<T> varlist, CreateRowDelegate<T> fn)
        {
            DataTable dtReturn = new DataTable();
            // column names
            PropertyInfo[] oProps = null;
            // Could add a check to verify that there is an element 0
            foreach (T rec in varlist)
            {
                // Use reflection to get property names, to create table, Only first time, others will follow
                if (oProps == null)
                {
                    oProps = ((Type)rec.GetType()).GetProperties();
                    foreach (PropertyInfo pi in oProps)
                    {
                        Type colType = pi.PropertyType; if ((colType.IsGenericType) && (colType.GetGenericTypeDefinition() == typeof(Nullable<>)))
                        {
                            colType = colType.GetGenericArguments()[0];
                        }
                        dtReturn.Columns.Add(new DataColumn(pi.Name, colType));
                    }
                }
                DataRow dr = dtReturn.NewRow(); foreach (PropertyInfo pi in oProps)
                {
                    dr[pi.Name] = pi.GetValue(rec, null) == null ? DBNull.Value : pi.GetValue(rec, null);
                }
                dtReturn.Rows.Add(dr);
            }
            return (dtReturn);
        }
        public delegate object[] CreateRowDelegate<T>(T t);

List<T> list = DAL.ToList();
dataGridView1.DataSource = list.ToDataTable(a => new object[] { list });