c# - removing duplicates in a list with linq

Question

Suppose you have a list of MyObject like this:

public class MyObject
{
  public int ObjectID {get;set;}
  public string Prop1 {get;set;}
}

How do you remove duplicates from a list where there could be multiple instance of objects with the same ObjectID.

Thanks.

Answer 1

You can use GroupBy() and select the first item of each group to achieve what you want - assuming you want to pick one item for each distinct ObjectId property:

var distinctList = myList.GroupBy(x => x.ObjectID)
                         .Select(g => g.First())
                         .ToList();

Alternatively there is also DistinctBy() in the MoreLinq project that would allow for a more concise syntax (but would add a dependency to your project):

var distinctList = myList.DistinctBy( x => x.ObjectID).ToList();