Helper class to allow comparing part of a key in linq groupby/join operations using a specific comparer

gistfile1.cs

/* Usage:
source.GroupBy (x => new {
    x.TeamId,
    x.Name.CompareUsing (StringComparer.OrdinalIgnoreCase)
})
*/

public struct KeyPart<T> : IEquatable<KeyPart<T>>
{
    private readonly IEqualityComparer<T> comparer;
    private readonly T value;

    public KeyPart (T value, IEqualityComparare<T> comparer)
    {
        this.value = value;
        this.comparer = comparer;
    }
    
    public override int GetHashCode ()
    {
        return comparer.GetHashCode (value);
    }

    public bool Equals (KeyPart<T> other)
    {
        return comparer.Equals (value, other.value);
    }
    
    public override bool Equals (object other)
    {
        return other is KeyPart<T> && Equals ((KeyPart<T>) other);
    }
}

public static class KeyPart
{
    public static KeyPart<T> CompareUsing<T> (this T value, IEqualityComparer<T> comparer)
    {
        return new KeyPart (value, comparer);
    }
}