Should I use values or keys?

Question

I am warpping an ArcGIS IFeature object with a class that has my required properties to get and set them easily. Basically, the get and set operations just use feature.get_value(index) and feature.set_value(indes, value), and expose the strongly typed value.
I have several fields that use a domain (basically, an IDictionary<string, object>) to represent common properties across the application.
At first I figured I would only use the keys of the domain (which are normal int values) in my wrapping class, and use the domain in my ToString() method, to translate to strings for the UI.
Later I figured out I can use strings in my applicaiton (which makes it easier to pass around nulls, as the actual domain fields are nullable most of the time), and only change those fields' getters and setters to use GetDomainValue(index) and SetDomainValue(index, value) method that will translate between the key and value to/from the underlying feature object.

What approach do you think is better? I figured the string approach is a bit more "persistent ignorant", as my class doesn't care how the values are being saved, just their string representation. On the other hand, it makes the code jump through loops a bit - instead of returning what's in the feature, every getter needs to iterate the domain.

Answer 1

You might want to think about representing your domain fields with Nullable< Int32>. This would give you a way to represent features that have a domain value specified but it also allows you to directly specify null where appropriate.

Answer 2

I ended up sticking with the domain values, so that I can also verify that the calling code passed a valid value.