What is the need for Hash Table and Serialization in .Net ?

 Posted by Bharathi Cherukuri on 1/30/2012 | Category: ASP.NET Interview questions | Views: 7852 | Points: 40

The Hashtable object contains items in key/value pairs. The keys are used as indexes. We can search value by using their corresponding key.
In .NET, the class that implements a hash table is the Hashtable class.

By using Add Method we can add elements to the Hashtable as shown below:

private Hashtable table = new Hashtable();

public void AddEntry(BookEntry entry)
table.Add( entry.GetPerson(), entry );

Once the Hashtable gets populated,you can search and retrieve data in it by calling the indexer for the Hashtable class as shown below:

public BookEntry GetEntry(Person key)

return (BookEntry) table[key];

You can also remove the records from the Hashtable by calling the Remove Method which takes a key identifying the element you want to remove as shown below:

public void DeleteEntry(Person key)

table.Remove( key );

The data populated from the Hashtable can be saved using Serialization process.
Serialization is a process where the object gets converted into a linear sequence of Bytes for storage or transmission to another location.
This process can be done by using BinaryFormater class which serializes Hashtable object to file stream.

public void Save()

Stream s = File.Open("Phone.bin", FileMode.Create, FileAccess.ReadWrite);
BinaryFormatter b = new BinaryFormatter();
b.Serialize(s, table);

By using the Deserialize method, you can get back the recovered Hashtable object as shown below:

s = File.Open("Phone.bin", FileMode.Open, FileAccess.Read);

BinaryFormatter b = new BinaryFormatter();
table = (Hashtable) b.Deserialize(s);

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Comments or Responses

Posted by: Chvrsri on: 1/30/2012 | Points: 10
Nice Post !! Keep posting !!!
Posted by: Bharathi Cherukuri on: 1/30/2012 | Points: 10
Hi Chvsri
Thank you..

Posted by: Akiii on: 1/31/2012 | Points: 10
Nice topic...

Thanks and Regards
Posted by: Bharathi Cherukuri on: 2/2/2012 | Points: 10
Hi Akiii

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