Template for simple equality implementation for C# classes

C# class equality operators and methods

// Public operators

public static bool operator ==(SomeClass item1, SomeClass item2)
{
    if (System.Object.ReferenceEquals(item1, item2))
        return true;

    if (((object)item1 == null) || ((object)item2 == null))
        return false;

    if ((item1.SomeSequence == null && item2.SomeSequence != null)
        ||
        (item1.SomeSequence != null && item2.SomeSequence == null))
    {
        return false;
    }

    bool areSomeSequenceSequencesEqual = false;

    if (item1.SomeSequence == null && item2.SomeSequence == null)
    {
        areSomeSequenceSequencesEqual = true;
    }
    else
    {
        areSomeSequenceSequencesEqual = item1.SomeSequence.SequenceEqual(item2.SomeSequence);
    }

    return
        item1._someField == item2._someField
        && areSomeSequenceSequencesEqual;
}

public static bool operator !=(SomeClass item1, SomeClass item2)
{
    return !(item1 == item2);
}


// Public methods

public override bool Equals(object obj)
{
    return Equals(obj as SomeClass);
}

public bool Equals(SomeClass other)
{
    return this == other;
}

public override int GetHashCode()
{
    return
        _someField.GetHashCode()
        ^ ((this.SomeSequence == null) ? 0 : this.SomeSequence.GetHashCode());
}