LINQ: How to get distinct results based on a specific field

Occasionally you may want to filter some resultset to be distinct based on some particular field, such as an ID. Here's how to do it with a custom IEqualityComparer.

public class MyComparer : IEqualityComparer<IMyTypeSearchResult>
    {
         public bool Equals(IMyTypeSearchResult x, IMyTypeSearchResult y)
         {
             return x.SomeField == y.SomeField ;
        }

        public int GetHashCode(IMyTypeSearchResult  obj)
         {
             return obj.SomeField.GetHashCode();
        }
     }


// Usage (original SearchResults contains duplicates based on SomeField):

   container.SearchResults = container.SearchResults.Distinct( new MyComparer() );

NOTE: It is important for your GetHashCode method to return a meaningful unique Hash for your object. Sometimes it can be a good idea to combine more than one property and then return the GetHashCode result of the composite.