LINQ orderby on date field in descending order

Question

How can I change the LINQ query in the code below to sort by date in descending order (latest first, earliest last)?

using System; using System.Linq; using System.Collections.Generic;   namespace Helloworld {     class MainClass     {         public static void Main (string[] args)         {             List<Envelops> env = new List<Envelops> ();             Envelops e = new Envelops { ReportDate = DateTime.Now };             env.Add (e);             e = new Envelops { ReportDate = DateTime.Now.AddDays (5) };             env.Add (e);             e = new Envelops { ReportDate = new DateTime (2011, 3, 3) };             env.Add (e);             e = new Envelops { ReportDate = DateTime.Now };             env.Add (e);              foreach (Envelops r in env) {                 Console.WriteLine (  r.ReportDate.ToString("yyyy-MMM"));             }              var ud = (from d in env                                   select  d.ReportDate.ToString("yyyy-MMM") ).Distinct();                   Console.WriteLine ("After distinct");              foreach (var r in ud) {                 Console.WriteLine (r);             }          }     }      class Envelops     {         public DateTime ReportDate { get; set; }     }  }`enter code here` 

the current output is:

2011-Apr 2011-May 2011-Mar 2011-Apr After distinct 2011-Apr 2011-May 2011-Mar 

I want the output to in the following order:

may april march order 

Answer 1

env.OrderByDescending(x => x.ReportDate) 

Answer 2

I don't believe that Distinct() is guaranteed to maintain the order of the set.

Try pulling out an anonymous type first and distinct/sort on that before you convert to string:

var ud = env.Select(d => new                           {                              d.ReportDate.Year,                              d.ReportDate.Month,                              FormattedDate = d.ReportDate.ToString("yyyy-MMM")                          })             .Distinct()             .OrderByDescending(d => d.Year)             .ThenByDescending(d => d.Month)             .Select(d => d.FormattedDate);