A Copy vs. a Reference
<p>Why does this code result in both shipment.Items.Count and combinedShipment.Items.Count equal to zero?</p>

<pre><code>private static InboundShipment CombineLikeIsbns(InboundShipment shipment)
{
    // shipment.Items has a count of 3

    var distinctIsbns = shipment.Items.Select(i =&gt; i.ISBN).Distinct().ToList();

    var combinedShipment = shipment;
    combinedShipment.Items = new List&lt;InboundShipmentItem&gt;();

    // Now both combinedShipment and shipment have an empty List in the .Items property

    ...

    return combinedShipment;
}
</code></pre>

<p>[EDIT]
And what can I do to avoid having shipment.Items set to new List when I set combinedShipment.Items to the same?</p>
