What is a good way to determine via server object model if a field supports multiple values?

Question

When looking at an SPField object, how can I tell if it supports multiple values?

I.e. a Choice field that is displayed using Checkboxes, a Managed Metadata field that allows multiple values, Person or Group that allows multiple selections, and quite possibly something I'm not thinking of?

The best I've come up with is compiling a list of multi valued types (e.g. TaxonomyFieldTypeMulti, LookupMulti, UserMulti..) and comparing against FieldTypeAsString. I'm wondering if there's a better approach.

Answer 1

Lookup fields (which user extends) supports AllowMultipleValues.

Then you can do:

var multi = field is SPFieldMultiChoice || 
    (field is SPFieldLookup && (field as SPFieldLookup).AllowMultipleValues);

Same for Taxonomy