Robust Dictionary Exception Handling

Question

I basically want to make sure I incorporate all exception handling possible for ArrayDictionary  below.

What are all the possible exception handling you can do for the dictionary and dictionary arrays below. I know a few contraints off the top, All three Dictionaries must have the number of items or count which is 5 items each after items are being added. If not we can't continue. Another contraint will be to ensure that the dictionary count is three. and you can also check is dictionary is not null.

What are more checks and balances or exception handling?

review the next reply.