How to get distinct records from a list

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I have a list of type `Myclass`

C#

List<Myclass> liSubjectIdDetail = new List<Myclass>();

where Myclass looks like

C#

public class  Myclass
  {
      public Nullable<decimal> SubjectId { get; set; }
      public string SubjectName { get; set; }
  }

I am adding records into liSubjectIdDetail from a table

C#

foreach (decimal Id in VarCEMSIdDetail)
  {
      liSubjectIdDetail.AddRange(db.Stt.MyTable.Where(x => x.Id == Id).Select(x => new Myclass { SubjectId = x.SubjectId, SubjectName = x.SubjectName }).ToList());
  }

where Id contains a list of certain Ids on the basis of which records I fetch.

Now I want to get only distinct records in this list.

I have tried it with hashtable in place of List
and I also tried

C#

liSubjectIdDetail= liSubjectIdDetail.Distinct().ToList();

but this too, is not working. Please give me a better solution.
Thanks in advance

Posted 23-Sep-13 22:08pm

Co. Aden

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OriginalGriff · Answer 1 · 2013-09-23T23:12:00

Well...it is working - just not the way you think it should.

It is indeed sorting out all the distinct values, but using the default Comparer - so if you haven't written a Comparer for your class it will just use the HashCode method, which will return all the records - since they will be different in some way!

If you want to use Distinct by a property of your class (get all the instances that have different SubjectName values for example) then you need to supply a new Comparer when you do call Distinct.
MSDN can help: http://msdn.microsoft.com/en-us/library/bb338049.aspx[^]