'System.Collections.Generic' best choice for a list of username and passwords

I have a set of u开发者_开发问答sername/password pairs. There are no duplicate usernames but passwords duplication is allowed.

Using System.Collections I have many choices for example:

List<Dictionary<string, string>> accounts;

// or

System.Collections.Specialized.NameValueCollection[] accounts;

All of us have the concepts of what a programmer needs with a set of username/password pair (get password of a known username, add a username/password ...).

Just use a Dictionary:

Dictionary<string, string> accounts

The type System.Collections.Specialized.NameValueCollection was part of the first version of .NET, before generics were available. It is better to use a generic collection where possible.

I'd also advise you not to store the passwords in plain text, in case that's what you are doing.

I think I would simply use

Dictionary<string, SecureString>

The keys in dictionary are unqiue. You can add/remove new user to your dictionary. You can lookup/change password from dictionary.

Sounds to me like you want a Hashtable.

What is the problem with using just a Dictionary<string, string>? It would allow you to do whatever you need. (Or maybe SortedDictionary<string, string> or SortedList<string, string> if you need fast retrieval)