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NameObjectCollectionBase.BaseGetKey Method

Gets the key of the entry at the specified index of the NameObjectCollectionBase instance.

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

'Declaration
Protected Function BaseGetKey ( _
	index As Integer _
) As String
'Usage
Dim index As Integer 
Dim returnValue As String 

returnValue = Me.BaseGetKey(index)

Parameters

index
Type: System.Int32

The zero-based index of the key to get.

Return Value

Type: System.String
A String that represents the key of the entry at the specified index.

ExceptionCondition
ArgumentOutOfRangeException

index is outside the valid range of indexes for the collection.

This method is an O(1) operation.

The following code example uses BaseGetKey and BaseGet to get specific keys and values.

Imports System
Imports System.Collections
Imports System.Collections.Specialized

Public Class MyCollection
   Inherits NameObjectCollectionBase

   Private _de As New DictionaryEntry()

   ' Gets a key-and-value pair (DictionaryEntry) using an index.
   Default Public ReadOnly Property Item(index As Integer) As DictionaryEntry
      Get
         _de.Key = Me.BaseGetKey(index)
         _de.Value = Me.BaseGet(index)
         Return _de
      End Get 
   End Property 

   ' Gets or sets the value associated with the specified key.
   Default Public Property Item(key As [String]) As [Object]
      Get 
         Return Me.BaseGet(key)
      End Get 
      Set 
         Me.BaseSet(key, value)
      End Set 
   End Property 

   ' Adds elements from an IDictionary into the new collection. 
   Public Sub New(d As IDictionary)
      Dim de As DictionaryEntry
      For Each de In  d
         Me.BaseAdd(CType(de.Key, [String]), de.Value)
      Next de
   End Sub 'New 

End Class 'MyCollection


Public Class SamplesNameObjectCollectionBase   

   Public Shared Sub Main()

      ' Creates and initializes a new MyCollection instance. 
      Dim d = New ListDictionary()
      d.Add("red", "apple")
      d.Add("yellow", "banana")
      d.Add("green", "pear")
      Dim myCol As New MyCollection(d)
      Console.WriteLine("Initial state of the collection (Count = {0}):", myCol.Count)
      PrintKeysAndValues(myCol)

      ' Gets specific keys and values.
      Console.WriteLine("The key at index 0 is {0}.", myCol(0).Key)
      Console.WriteLine("The value at index 0 is {0}.", myCol(0).Value)
      Console.WriteLine("The value associated with the key ""green"" is {0}.", myCol("green"))

   End Sub 'Main

   Public Shared Sub PrintKeysAndValues(myCol As MyCollection)
      Dim i As Integer 
      For i = 0 To myCol.Count - 1
         Console.WriteLine("[{0}] : {1}, {2}", i, myCol(i).Key, myCol(i).Value)
      Next i
   End Sub 'PrintKeysAndValues

End Class 'SamplesNameObjectCollectionBase 


'This code produces the following output. 

'Initial state of the collection (Count = 3): 
'[0] : red, apple 
'[1] : yellow, banana 
'[2] : green, pear 
'The key at index 0 is red. 
'The value at index 0 is apple. 
'The value associated with the key "green" is pear.

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
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