using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        var widgets = new HashSet<Widget>(Widget.NameComparer) {

            new Widget { Name = "Test1" },

            new Widget { Name = "test1" }

        };

        Console.WriteLine(widgets.Count);

    }

}

​

public class Widget

{

    public string Name

    {

        get;

        set;

    }

    private sealed class NameEqualityComparer : IEqualityComparer<Widget>

    {

        public bool Equals(Widget x, Widget y)

        {

            if (ReferenceEquals(x, y))

            {

                return true;

            }

            if (ReferenceEquals(x, null))

            {

                return false;

            }

            if (ReferenceEquals(y, null))

            {

                return false;

            }

            if (x.GetType() != y.GetType())

            {

                return false;

            }

            return string.Equals(x.Name, y.Name, StringComparison.OrdinalIgnoreCase);

        }

        public int GetHashCode(Widget obj)

        {

            return (obj.Name != null ? obj.Name.GetHashCode() : 0);

        }

    }

    private static readonly IEqualityComparer<Widget> NameComparerInstance = new NameEqualityComparer();

    public static IEqualityComparer<Widget> NameComparer

    {

        get

        {

            return NameComparerInstance;

        }

    }

}