What is the best .NET type for collections where each key can have multiple values?

I have one key but different values for that key. I tried HashTable but I don't think that is the right way of doing it.

I'll explain in detail what the requirement is:

I have a Key - "Asp.net" - for that I have n number of values - 61, 67, 100

So I have t开发者_开发问答o store this somewhere like Dictionary or hash table.

A Dictionary<string, List<int>> would do the trick for your sample data.

You could use a Dictionary<string, List<int>>:

var dictionary = new Dictionary<string, List<int>>();
dictionary.Add("asp.net", new List<int>());
dictionary["asp.net"].Add(61);
dictionary["asp.net"].Add(67);
dictionary["asp.net"].Add(100);

I think you want PowerCollections MultiDictionary.

http://www.codeplex.com/PowerCollections

If both your key and values are string you may want to use NameValueCollection.

NameValueCollection class stores multiple string values under a single key. Acording to MSDN, this class can be used for headers, query strings and form data.