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TreeNodeCollection Class

Represents a collection of TreeNode objects.

Namespace:  System.Windows.Forms
Assembly:  System.Windows.Forms (in System.Windows.Forms.dll)

Public Class TreeNodeCollection _
	Implements IList, ICollection, IEnumerable
Dim instance As TreeNodeCollection

The Add, Remove, and RemoveAt methods enable you to add and remove individual tree nodes from the collection.


Enumerating the collection and removing nodes is not supported.

You can also use the AddRange or Clear methods to add or remove all the tree nodes from the collection.

Classes cannot inherit from the TreeNodeCollection class.

The following code example displays customer information in a TreeView control. The root tree nodes display customer names, and the child tree nodes display the order numbers assigned to each customer. In this example, 1,000 customers are displayed with 15 orders each. The repainting of the TreeView is suppressed by using the BeginUpdate and EndUpdate methods, and a wait Cursor is displayed while the TreeView creates and paints the TreeNode objects. This example requires that you have a Customer object that can hold a collection of Order objects. It also requires that you have created an instance of a TreeView control on a Form.

Public Class Customer
   Inherits [Object]
   Private custName As String = "" 
   Friend custOrders As New ArrayList()

   Public Sub New(ByVal customername As String)
      Me.custName = customername
   End Sub 

   Public Property CustomerName() As String 
         Return Me.custName
      End Get 
      Set(ByVal Value As String)
         Me.custName = Value
      End Set 
   End Property 

   Public ReadOnly Property CustomerOrders() As ArrayList
         Return Me.custOrders
      End Get 
   End Property 
End Class 'End Customer class

Public Class Order
   Inherits [Object]
   Private ordID As String 

   Public Sub New(ByVal orderid As String)
      Me.ordID = orderid
   End Sub 'New 

   Public Property OrderID() As String 
         Return Me.ordID
      End Get 
      Set(ByVal Value As String)
         Me.ordID = Value
      End Set 
   End Property 
End Class ' End Order class

' Create a new ArrayList to hold the Customer objects. 
Private customerArray As New ArrayList()

Private Sub FillMyTreeView()
   ' Add customers to the ArrayList of Customer objects. 
   Dim x As Integer 
   For x = 0 To 999
      customerArray.Add(New Customer("Customer" + x.ToString()))
   Next x

   ' Add orders to each Customer object in the ArrayList. 
   Dim customer1 As Customer
   For Each customer1 In customerArray
      Dim y As Integer 
      For y = 0 To 14
         customer1.CustomerOrders.Add(New Order("Order" + y.ToString()))
      Next y
   Next customer1

   ' Display a wait cursor while the TreeNodes are being created.
   Cursor.Current = New Cursor("MyWait.cur")

   ' Suppress repainting the TreeView until all the objects have been created.

   ' Clear the TreeView each time the method is called.

   ' Add a root TreeNode for each Customer object in the ArrayList. 
   Dim customer2 As Customer
   For Each customer2 In customerArray
      treeView1.Nodes.Add(New TreeNode(customer2.CustomerName))

      ' Add a child TreeNode for each Order object in the current Customer object. 
      Dim order1 As Order
      For Each order1 In customer2.CustomerOrders
         treeView1.Nodes(customerArray.IndexOf(customer2)).Nodes.Add( _
    New TreeNode(customer2.CustomerName + "." + order1.OrderID))
      Next order1
   Next customer2

   ' Reset the cursor to the default for all controls.
   Cursor.Current = System.Windows.Forms.Cursors.Default

   ' Begin repainting the TreeView.
End Sub 'FillMyTreeView


Any public static (Shared in Visual Basic) members of this type are thread safe. Any instance members are not guaranteed to be thread safe.

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

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