VB.Net/Data Structure/HashTable

Hashtable: add,get,count, Dictionary Key and value Enumerator

<source lang="vbnet"> Imports System Imports System.Collections Public Class MainClass

  Public Shared Sub Main()
     Dim table As Hashtable = New Hashtable() 
  
     Dim employee As New Employee("First Name", "Last Name")
     Try
        table.Add("Last Name", employee)
        Console.WriteLine("Put: " & employee.ToString())
     Catch argumentException As ArgumentException
        Console.WriteLine(argumentException.ToString())
     End Try
     Dim result As Object = table("Last Name")
     If Not result Is Nothing Then
        Console.WriteLine("Get: " & result.ToString())
     Else
        Console.WriteLine("Get: " & "Last Name" & " not in table")
     End If

     table.Remove("Last Name")
     Console.WriteLine("table count: " & table.Count)
     Console.WriteLine("Contains key: " & table.ContainsKey("Last Name"))
     table.Clear()
     Dim enumerator As IDictionaryEnumerator = table.GetEnumerator()
     While enumerator.MoveNext()
        Console.WriteLine(Convert.ToString(enumerator.Value))
     End While

     enumerator = table.GetEnumerator()
     While enumerator.MoveNext()
        Console.WriteLine(enumerator.Key )
     End While
  End Sub

End Class

Public Class Employee

  Private firstName, lastName As String
  Public Sub New(ByVal first As String, ByVal last As String)
     firstName = first
     lastName = last
  End Sub 
  Public Overrides Function ToString() As String
     Return firstName & " " & lastName
  End Function 

End Class

      </source>

Store Environment Variables into a Hash table

<source lang="vbnet"> Imports System Imports System.Collections Imports System.Environment

Public Class MainClass

 Shared Sub Main()
     Dim eVariables As Hashtable
     eVariables = CType(GetEnvironmentVariables(), Hashtable)
     Dim thing As Object
     For Each thing In eVariables.Keys
           Console.WriteLine("The environment variable named " & thing.ToString() _
           & " has value " & eVariables(thing).ToString())
     Next
 End Sub

End Class

      </source>