ContainsKey : Hashtable « Collections « VB.Net Tutorial

1. VB.Net Tutorial
2. Collections
3. Hashtable

Imports System.Collections

public class Test
   public Shared Sub Main
        Dim myTable As New Hashtable
        Dim objKey As Object
        Dim objValue As Object

        'Populate the hash table.
        myTable.Add("H", 1)
        myTable.Add("L", 2)

        'Check before inserting another value.
        If Not myTable.ContainsKey("A") Then
            myTable.Add("A", 78)
        End If

        'Remove a value.
        myTable.Remove("L")

        'Display the hash table values.
        Console.WriteLine("The hash table contains " & myTable.Count & " elements.")
        For Each objKey In myTable.Keys
            objValue = myTable.Item(objKey)
            Console.WriteLine("ELEMENT KEY: " & objKey.ToString & vbCrLf & _
                   "ELEMENT VALUE: " & objValue.ToString)
        Next objKey



   End Sub
End class

The hash table contains 2 elements.
ELEMENT KEY: A
ELEMENT VALUE: 78
ELEMENT KEY: H
ELEMENT VALUE: 1