Use linq distinct function?

This question already has an answer here:

LINQ's Distinct() on a particular property 17 answers

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You could use GroupBy on an anonymous type with both properties to make them distinct:

var coursesList = 
     from c in not_subsribe
     group c by new { Id = c.Cours.ID, Name = c.Cours.Name } into g
     order by g.Key.Name
     select new SelectListItem
     {
         Text = g.Key.Name,
         Value = g.Key.Id
     };

That works because an anonymous type automatically overrides Equals + GetHashCode for you what is needed for GroupBy or Distinct . So now you could also use Distinct :

var coursesList = not_subsribe
.Select(c => new { Id = c.Cours.ID, Name = c.Cours.Name })
.Distinct()
.OrderBy(x => x.Name)
.Select(x => new SelectListItem
     {
         Text = g.Key.Name,
         Value = g.Key.Id
     }); 

---

You can use:

var coursesList = courses.DistinctBy(c => courses.Cours.Name)
                         .Select(crs => new SelectListItem
                                          {
                                              Text = crs.Cours.Name,
                                              Value = crs.Cours.ID.ToString()
                                          });

Sorry, I forgot to mention that DistinctBy method is available in a 3rd party library called MoreLINQ . This library is available for download using Nuget Package manager from here: http://www.nuget.org/packages/morelinq/

And you can find out more about MoreLINQ from here: https://code.google.com/p/morelinq/

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