What is the generic version of a Hashtable?

Question

I have been learning the basics of generics in .NET. However, I don't see the generic equivalent of Hashtable. Please share some sample C# code for creating generic hashtable classes.

Answer 1

Dictionary<TKey, TValue>

Note that Dictionary is not a 100% drop in replacement for HashTable.

There is a slight difference in the way they handle NULLs. The dictionary will throw an exception if you try to reference a key that doesn't exist. The HashTable will just return null. The reason is that the value might be a value type, which cannot be null. In a Hashtable the value was always Object, so returning null was at least possible.

Answer 2

The generic version of Hashtable class is System.Collections.Generic.Dictionary class.

Sample code:

Dictionary<int, string> numbers = new Dictionary<int, string>( );    numbers.Add(1, "one");    numbers.Add(2, "two");    // Display all key/value pairs in the Dictionary.    foreach (KeyValuePair<int, string> kvp in numbers)    {       Console.WriteLine("Key: " + kvp.Key + "\tValue: " + kvp.Value);    }