What should GetHashCode return when object's identifier is null?

Question

Which of the following is correct/better, considering that identity property could be null.

public override int GetHashCode()
{
    if (ID == null) {
        ret         


        

Answer 1

Perhaps what you want is something like this?

override int GetHashCode()
{
    if (ID != null)
        return ID.GetHashCode();

    return DBNull.Value.GetHashCode();
}

The important thing is this, should two objects with null IDs be considered equal?