This documentation is archived and is not being maintained.

Hashtable.Remove Method

Removes the element with the specified key from the Hashtable.

Namespace:  System.Collections
Assembly:  mscorlib (in mscorlib.dll)

public function Remove(
	key : Object


Type: System.Object

The key of the element to remove.




key is a null reference (Nothing in Visual Basic).


The Hashtable is read-only.


The Hashtable has a fixed size.

If the Hashtable does not contain an element with the specified key, the Hashtable remains unchanged. No exception is thrown.

This method is an O(1) operation.

The following example shows how to remove elements from the Hashtable.

import System
import System.Collections
import Microsoft.VisualBasic

// Creates and initializes a new Hashtable.
var myHT : Hashtable = new Hashtable()
myHT.Add("1a", "The")
myHT.Add("1b", "quick")
myHT.Add("1c", "brown")
myHT.Add("2a", "fox")
myHT.Add("2b", "jumped")
myHT.Add("2c", "over")
myHT.Add("3a", "the")
myHT.Add("3b", "lazy")
myHT.Add("3c", "dog")

// Displays the Hashtable.
Console.WriteLine("The Hashtable initially contains the following:")

// Removes the element with the key "3b".

// Displays the current state of the Hashtable.
Console.WriteLine("After removing \"lazy\":")

function PrintKeysAndValues(myList : Hashtable){
    var myEnumerator : IDictionaryEnumerator = myList.GetEnumerator()
        Console.WriteLine("\t{0}:\t{1}", myEnumerator.Key, myEnumerator.Value)

// This code produces the following output.
// The Hashtable initially contains the following:
//     -KEY-    -VALUE-
//     3a:      the
//     3c:      dog
//     3b:      lazy
//     1c:      brown
//     1b:      quick
//     1a:      The
//     2a:      fox
//     2b:      jumped
//     2c:      over
// After removing "lazy":
//     -KEY-    -VALUE-
//     3a:      the
//     3c:      dog
//     1c:      brown
//     1b:      quick
//     1a:      The
//     2a:      fox
//     2b:      jumped
//     2c:      over 

Windows 7, Windows Vista, Windows XP SP2, Windows XP Media Center Edition, Windows XP Professional x64 Edition, Windows XP Starter Edition, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003, Windows Server 2000 SP4, Windows Millennium Edition, Windows 98, Windows CE, Windows Mobile for Smartphone, Windows Mobile for Pocket PC, Xbox 360, Zune

The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

.NET Framework

Supported in: 3.5, 3.0, 2.0, 1.1, 1.0

.NET Compact Framework

Supported in: 3.5, 2.0, 1.0

XNA Framework

Supported in: 3.0, 2.0, 1.0