Dictionary:
1. Dictionary throws an exception if we try to find a key which does not
exist in current collection.
For example:
In the Dictionary,
no need boxing
and unboxing. i.e.
var employees
= new Dictionary<string, Employee>();
Employee emp = employees ["Anil Singh"];
In the Hashtable,
need to boxing and
unboxing. i.e.
var employees
= new Hashtable();
Employee emp = customers["Anil Singh"] as Employee;
3. When we creating dictionary, we must declare the data types of both
keys and values.
4. Dictionary is a generic type and type-safe. i.e.
Dictionary<char, int> dic = new Dictionary<char, int>();
Hashtable:
1. Hashtable returns null values if we try to find a key which does not
exist in current collection.
2. It is slower than dictionary because it requires boxing and unboxing.
For example:
In the Dictionary,
no need boxing
and unboxing. i.e.
var employees
= new Dictionary<string, Employee>();
Employee emp = employees ["Anil Singh"];
In the Hashtable,
need to boxing and
unboxing. i.e.
var employees
= new Hashtable();
Employee emp = customers["Ali G"] as Employee;
3. All the members in a Hashtable are thread safe.
4. When we creating Hashtable, we no need to declare the data types.
5. Hashtable is not a generic type and It is loosely-typed data
structure.
6. In Hashtable, we can add any type of keys and values.
Example for Dictionary vs. HashTable
as given below.
public class Dictionary
{
/// <summary>
/// </summary>
static void Main(string[] args)
{
Dictionary<int, string> dicList = new Dictionary<int, string>();
dicList.Add(10, "A10");
dicList.Add(21, "B21");
dicList.Add(33, "C33");
foreach (KeyValuePair<int, String> pair in dicList)
{
Console.WriteLine(pair.Key
+ " "
+ pair.Value);
}
Console.ReadLine();
}
}
The
output for dictionary
public class Hashtable_Example
{
/// <summary>
/// </summary>
/// <param
name="args"></param>
static void Main(string[] args)
{
Hashtable hasList = new Hashtable();
hasList.Add(1, 100);
hasList.Add(2, "A2");
hasList.Add(3, hasList);
foreach (DictionaryEntry entry in hasList)
{
int Key = (int)entry.Key; //Casting
string value =
entry.Value.ToString(); //Casting
Console.WriteLine((int)entry.Key + " " +
entry.Value.ToString());
}
Console.ReadLine();
}
}
The
output for HashTable
