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TreeNodeCollection Class

Represents a collection of TreeNode objects.

For a list of all members of this type, see TreeNodeCollection Members.

System.Object
   System.Windows.Forms.TreeNodeCollection

[Visual Basic]
Public Class TreeNodeCollection
   Implements IList, ICollection, IEnumerable
[C#]
public class TreeNodeCollection : IList, ICollection, IEnumerable
[C++]
public __gc class TreeNodeCollection : public IList, ICollection,
   IEnumerable
[JScript]
public class TreeNodeCollection implements IList, ICollection,
   IEnumerable

Thread Safety

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

Remarks

The Add, Remove, and RemoveAt methods enable you to add and remove individual tree nodes from the collection. You can also use the AddRange or Clear methods to add or remove all the tree nodes from the collection.

Example

[Visual Basic, C#, C++] The following 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 assumes you have a Customer object that can hold a collection of Order objects. It also assumes that you have created an instance of a TreeView control on a Form.

[Visual Basic] 
' 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.
   treeView1.BeginUpdate()

   ' Clear the TreeView each time the method is called.
   treeView1.Nodes.Clear()

   ' 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.
   treeView1.EndUpdate()
End Sub 'FillMyTreeView

[C#] 
// Create a new ArrayList to hold the Customer objects.
private ArrayList customerArray = new ArrayList(); 

private void FillMyTreeView()
{
   // Add customers to the ArrayList of Customer objects.
   for(int x=0; x<1000; x++)
   {
      customerArray.Add(new Customer("Customer" + x.ToString()));
   }

   // Add orders to each Customer object in the ArrayList.
   foreach(Customer customer1 in customerArray)
   {
      for(int y=0; y<15; y++)
      {
         customer1.CustomerOrders.Add(new Order("Order" + y.ToString()));    
      }
   }

   // 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.
   treeView1.BeginUpdate();

   // Clear the TreeView each time the method is called.
   treeView1.Nodes.Clear();

   // Add a root TreeNode for each Customer object in the ArrayList.
   foreach(Customer customer2 in customerArray)
   {
      treeView1.Nodes.Add(new TreeNode(customer2.CustomerName));
          
      // Add a child treenode for each Order object in the current Customer object.
      foreach(Order order1 in customer2.CustomerOrders)
      {
         treeView1.Nodes[customerArray.IndexOf(customer2)].Nodes.Add(
           new TreeNode(customer2.CustomerName + "." + order1.OrderID));
      }
   }

   // Reset the cursor to the default for all controls.
   Cursor.Current = Cursors.Default;

   // Begin repainting the TreeView.
   treeView1.EndUpdate();
}

[C++] 
void FillMyTreeView() {
    // Add customers to the ArrayList of Customer objects.
    for (int x=0; x<1000; x++) {
        customerArray->Add(new Customer(String::Concat(S"Customer ", __box(x))));
    }

    // Add orders to each Customer object in the ArrayList.
    IEnumerator* myEnum = customerArray->GetEnumerator();
    while (myEnum->MoveNext()) {
        Customer* customer1 = __try_cast<Customer*>(myEnum->Current);

        for (int y=0; y<15; y++) {
            customer1->CustomerOrders->Add(new Order(String::Concat(S"Order ", __box(y))));
        }
    }

    // Display a wait cursor while the TreeNodes are being created.
    Cursor::Current = new System::Windows::Forms::Cursor(S"MyWait.cur");

    // Suppress repainting the TreeView until all the objects have been created.
    treeView1->BeginUpdate();

    // Clear the TreeView each time the method is called.
    treeView1->Nodes->Clear();

    // Add a root TreeNode for each Customer object in the ArrayList.
    while (myEnum->MoveNext()) {
        Customer* customer2 = __try_cast<Customer*>(myEnum->Current);

        treeView1->Nodes->Add(new TreeNode(customer2->CustomerName));

        // Add a child treenode for each Order object in the current Customer object.
        IEnumerator* myEnum = customer2->CustomerOrders->GetEnumerator();
        while (myEnum->MoveNext()) {
            Order* order1 = __try_cast<Order*>(myEnum->Current);

            treeView1->Nodes->Item[customerArray->IndexOf(customer2)]->Nodes->Add(
                new TreeNode(String::Concat(customer2->CustomerName, S".", order1->OrderID)));
        }
    }

    // Reset the cursor to the default for all controls.
    Cursor::Current = Cursors::Default;

    // Begin repainting the TreeView.
    treeView1->EndUpdate();
}

[JScript] No example is available for JScript. To view a Visual Basic, C#, or C++ example, click the Language Filter button Language Filter in the upper-left corner of the page.

Requirements

Namespace: System.Windows.Forms

Platforms: Windows 98, Windows NT 4.0, Windows Millennium Edition, Windows 2000, Windows XP Home Edition, Windows XP Professional, Windows Server 2003 family, .NET Compact Framework

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

See Also

TreeNodeCollection Members | System.Windows.Forms Namespace | TreeView | TreeNode

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