using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

​

public class Program

{

    public static void Main()

    {

              List<ItemDetails> theTempList = new List<ItemDetails>();

        List<ItemDetails> theOriList = new List<ItemDetails>();

        DateTime minDate = new DateTime(2016, 1, 1);

        DateTime maxDate = new DateTime(2016, 1, 1);

        int count;

​

        theOriList.Add(new ItemDetails("S1","S2", new DateTime(2016,1,1), new DateTime(2016,1,15)));

        theOriList.Add(new ItemDetails("S2", "S3", new DateTime(2016, 2, 1), new DateTime(2016, 2, 14)));

        theOriList.Add(new ItemDetails("S1", "S2", new DateTime(2016, 1, 5), new DateTime(2016, 1, 20)));

        theOriList.Add(new ItemDetails("S2", "S3", new DateTime(2016, 1, 25), new DateTime(2016, 2, 25)));

        theOriList.Add(new ItemDetails("S1", "S2", new DateTime(2016, 1, 21), new DateTime(2016, 1, 25)));

​

​

        theOriList.GroupBy(x=> new {x.From, x.To })

            .Select(x=> new ItemDetails(x.Key.From,x.Key.To,x.Min(m=>m.FromDate), x.Max(m=>m.ToDate)))

            .Dump();

    }

}

​

public class ItemDetails

{

     public string From;

     public string To;

    public DateTime FromDate;

    public DateTime ToDate;

    public ItemDetails(string from1, string to, DateTime fromDate, DateTime toDate)

    {

        From  = from1;

        To = to;

        FromDate = fromDate;

        ToDate = toDate;

    }

}