For elements with a maximum cardinality > 1, the API has a list of the type for that element.

../../_images/fhir_cardinality.png ../../_images/patient_identifier.png

To work with data in a list, you can use the standard C# List methods.

So for example, if we want to add the Identifier we created in the previous paragraph to the Identifier field of the instance of Patient we created earlier, we can do this:



If you did not initialize a field before adding to the list, the API will create the List for you, and will not generate a NullReferenceException.