Differences between Hashtable and Dictionary

When using large collection of key value pairs hashtable would be considered more
 efficient than dictionary.
 When we retrieve the record in collection the hashtable does not maintain the order
 of entries while dictionary maintains the order of entries by which entries were added.
 Dictionary relies on chaining whereas Hashtable relies on rehashing.

Dictionary:

·         It returns error if we try to find a key which does not exist.

·         It is faster than a Hashtable because there is no boxing and unboxing.

·         Only public static members are thread safe.

·         Dictionary is a generic type which means we can use it with any data type.

Hashtable:

·         It returns null if we try to find a key which does not exist.

·         It is slower than dictionary because it requires boxing and unboxing.

·         All the members in a Hashtable are thread safe,

·         Hashtable is not a generic type,