inq to datatable group by 多列 实现

using System;
using System.Collections.Generic;
using System.Data;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace ConsoleApplication2
{
    internal class Program
    {
        private static void Main(string[] args)
        {
            DataTable dt = new DataTable();
            dt.Columns.Add("type", typeof (string));
            dt.Columns.Add("time", typeof (string));
            dt.Columns.Add("action", typeof (string));
            dt.Columns.Add("sum", typeof (string));

            dt.Rows.Add("A", "09:00:00", "举手", "5");
            dt.Rows.Add("A", "15:00:00", "扭腰", "3");
            dt.Rows.Add("A", "19:00:00", "扭腰", "3");

            dt.Rows.Add("B", "08:00:00", "抬脚", "2");
            dt.Rows.Add("B", "11:00:00", "举手", "2");

            dt.Rows.Add("C", "08:00:00", "扭脖子", "6");
            dt.Rows.Add("C", "09:00:00", "提臀", "5");
            var query = from t in dt.AsEnumerable()
                group t by new
                {
                    t1 = t.Field<string>("type")
                    //,t2 = t.Field<DateTime>("arrivalTime")多个条件
                }
                into m
                select new
                {
                    time = string.Join("---", m.Select(n => n.Field<string>("time")).ToArray()),
                    type = m.Key.t1,
                    action = string.Join("/", m.Select(n => n.Field<string>("action")).ToArray()),
                    rowcount = m.Count()
                };
              var sss = query.ToList();

     
        }
    }
}