Linq实现DataTable的分组统计

DataTable dt = GetTestData(10); //获取10条测试数据
                var queryByService = from r in dt.AsEnumerable()
                            group r by r.Field<string>(4) into g
                            select new
                            {
                                Service = g.Key,
                                Bookings = g.Count(p => p.Field<string>(1) !=""),
                                ConfirmedBookings = g.Count(p => p.Field<string>(1) =="Confirmed"),
                                PendingBookings = g.Count(p => p.Field<string>(1) =="Pending"),
                                CancelledBookings = g.Count(p => p.Field<string>(1) =="Cancelled")
                            };
                var queryByClient = from r in dt.AsEnumerable()
                                    where r.Field<string>(1) =="Confirmed"
                            group r by r.Field<string>(5) into g
                            select new
                            {
                                BookingClient = g.Key,
                                _20DV = g.Count(p => p.Field<string>(2)=="20DV"),
                                _40DV = g.Count(p => p.Field<string>(2) =="40DV"),
                                _40HC = g.Count(p => p.Field<string>(2) =="40HC"),
                                Bookings = g.Count(),
                                TotalOceanFreight = g.Sum(p => p.Field<decimal>(3)),
                                AverageOceanFreight = g.Average(p => p.Field<decimal>(3))
                            };
                var queryByType = from r in dt.AsEnumerable()
                                    group r by r.Field<string>(2) into g
                                    select new
                                    {
                                        EquipmentType = g.Key,
                                        Total = g.Count(),
                                        Confirmed = g.Count(p => p.Field<string>(1) =="Confirmed"),
                                        Pending = g.Count(p => p.Field<string>(1) =="Pending"),
                                        Cancelled = g.Count(p => p.Field<string>(1) =="Cancelled")
                                    };
                GridView1.DataSource = dt;
                GridView1.DataBind();
                GridView2.DataSource = queryByService;
                GridView2.DataBind();
                GridView3.DataSource = queryByClient;
                GridView3.DataBind();   

                DataTable dtByType = ConvertToDataTable(queryByType);
                GridView4.DataSource = dtByType; //或 GridView4.DataSource = queryByType;
                GridView4.DataBind();  

另外ConvertToDataTable()是在网上看到的方法

public DataTable ConvertToDataTable<T>(IEnumerable<T> varlist)
        {
            DataTable dtReturn =new DataTable();
            // column names
            PropertyInfo[] oProps =null;
            if (varlist ==null) return dtReturn;
            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;
        }