Difference between Dictionary and Hashtable

Dictionary

“System.Collections.Generic.Dictionary<object,object>”

Dictionary<TKey,TValue> is a generic type, allowing:

 

• static typing (and compile-time verification)
• use without boxing

If you are .NET 2.0 or above, you should prefer Dictionary<TKey,TValue> (and the other generic collections)

Hashtable

“System.Collections.Hashtable”

Hashtable is of collection type.

A subtle but important difference is that Hashtable supports multiple reader threads with a single writer thread, while Dictionary offers no thread safety.

If you need thread safety with a generic dictionary, you must implement your own synchronization or (in .NET 4.0) use ConcurrentDictionary<TKey, TValue>.

Best of Luck.