Comparer

  public class FillOneDollarShareComparer : IEqualityComparer<FillOneDollarShareEntity>
        {
            // Products are equal if their names and product numbers are equal.
            public bool Equals(FillOneDollarShareEntity x, FillOneDollarShareEntity y)
            {

                //Check whether the compared objects reference the same data.
                if (ReferenceEquals(x, y)) return true;

                //Check whether any of the compared objects is null.
                if (ReferenceEquals(x, null) || ReferenceEquals(y, null))
                    return false;

                //Check whether the products' properties are equal.
                return x.id == y.id;
            }

            // If Equals() returns true for a pair of objects 
            // then GetHashCode() must return the same value for these objects.

            public int GetHashCode(FillOneDollarShareEntity entity)
            {
                //Check whether the object is null
                if (ReferenceEquals(entity, null)) return 0;

                //Get hash code for the Name field if it is not null.
                int hashID = entity.id.GetHashCode();

                //Calculate the hash code for the product.
                return hashID;
            }
        }