using System;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        // Student collection

        IList<File> filesList = new List<File>() 

        { 

                new File() { FileName="GCUS.zip", FileTimeStamp = DateTime.Parse("2.21.2019")} ,

                new File() { FileName="GCUS.zip", FileTimeStamp = DateTime.Parse("2.20.2019")} ,

                new File() { FileName="GCUS.zip", FileTimeStamp = DateTime.Parse("2.19.2019")} ,

                new File() { FileName="GCUS.zip", FileTimeStamp = DateTime.Parse("2.18.2019")} ,

                new File() { FileName="GCUS.zip", FileTimeStamp = DateTime.Parse("2.17.2019")} ,

                new File() { FileName="GACS.zip", FileTimeStamp = DateTime.Parse("2.21.2019")} ,

                new File() { FileName="GACS.zip", FileTimeStamp = DateTime.Parse("2.20.2019")} ,

                new File() { FileName="GACS.zip", FileTimeStamp = DateTime.Parse("2.19.2019")} ,

                new File() { FileName="GACS.zip", FileTimeStamp = DateTime.Parse("2.18.2019")} ,

                new File() { FileName="GACS.zip", FileTimeStamp = DateTime.Parse("2.17.2019")} 

        };

        // LINQ Query Syntax to distinct file names

        var groupedFiles =  from x in filesList

                            group x by x.FileName into A

                            select new  //new distinct list

                            {

                                FileName = A.Key,

                                FileTimeStamp = A.Max(x=>x.FileTimeStamp)

                            };

        var results = (

                        from  f in filesList

                        join g in groupedFiles on 

                                                    f.FileName equals g.FileName

                                                    where f.FileTimeStamp == g.FileTimeStamp

                        select f

                      ).ToList();

        //list results                

        foreach(var d in results){          

            Console.WriteLine(d.FileName + " " + d.FileTimeStamp);

        }

    }

}

​

//class definition

public class File{

    public string FileName { get; set; }

    public DateTime FileTimeStamp { get; set; }

}

​