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Hashtable in C#

By Mahesh Chand on Nov 14, 2005
Hashtable is useful when you need to store data in a key and value pair. This article shows how to use hashtable in C#.
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This quick how do I shows how to use a Hashtable in C#.

Creating a Hashtable

The Hashtable class in C# represents a hashtable. The following code creates a Hashtable:

private Hashtable hshTable = new Hashtable();

Adding Items to a Hashtable

Add method of Hashtable is used to add items to the hashtable. The method has index and value parameters. The following code adds three items to hashtable.

hshTable .Add("Author1",  "Mahesh Chand");
hshTable .Add("Author2",  "James Brand");
hshTable .Add("Author3",  "Mike Gold");

Retrieving an Item Value from Hashtable

The following code returns the value of "Author1" key:

string name = hshTable["Author1"].ToString();

Removing Items from a Hashtable

The Remove method removes an item from a Hashtable. The following code removes item with index "Author1" from the hashtable:

hshTable.Remove("Author1");

Looking through all Items of a Hashtable

The following code loops through all items of a hashtable and reads the values.

// Loop through all items of a Hashtable
IDictionaryEnumerator en = hshTable.GetEnumerator();
while (en.MoveNext())
{
      string str = en.Value.ToString();
}

Mahesh Chand

C# Corner founder, 10-times Microsoft MVP, technical author, and software architect. Mahesh authored his first book, A Programmer’s Guide to ADO.NET in C# with APress at the age of 25. C# Corner is a memb... Read more

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