TreeNodeCollection Class

Definition

Namespace:

System.Windows.Forms

Assembly:

System.Windows.Forms.dll

Represents a collection of TreeNode objects.

public ref class TreeNodeCollection : System::Collections::IList

public class TreeNodeCollection : System.Collections.IList

type TreeNodeCollection = class
    interface IList
    interface ICollection
    interface IEnumerable

Public Class TreeNodeCollection
Implements IList

Inheritance

Object

TreeNodeCollection

Implements

ICollection IEnumerable IList

Examples

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.

// The basic Customer class.
ref class Customer: public System::Object
{
private:
   String^ custName;

protected:
   ArrayList^ custOrders;

public:
   Customer( String^ customername )
   {
      custName = "";
      custOrders = gcnew ArrayList;
      this->custName = customername;
   }


   property String^ CustomerName 
   {
      String^ get()
      {
         return this->custName;
      }

      void set( String^ value )
      {
         this->custName = value;
      }

   }

   property ArrayList^ CustomerOrders 
   {
      ArrayList^ get()
      {
         return this->custOrders;
      }

   }

};


// End Customer class
// The basic customer Order class.
ref class Order: public System::Object
{
private:
   String^ ordID;

public:
   Order( String^ orderid )
   {
      ordID = "";
      this->ordID = orderid;
   }


   property String^ OrderID 
   {
      String^ get()
      {
         return this->ordID;
      }

      void set( String^ value )
      {
         this->ordID = value;
      }

   }

};
// End Order class



void FillMyTreeView()
{
   // Add customers to the ArrayList of Customer objects.
   for ( int x = 0; x < 1000; x++ )
   {
      customerArray->Add( gcnew Customer( "Customer " + x ) );
   }
   
   // Add orders to each Customer object in the ArrayList.
   IEnumerator^ myEnum = customerArray->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Customer^ customer1 = safe_cast<Customer^>(myEnum->Current);
      for ( int y = 0; y < 15; y++ )
      {
         customer1->CustomerOrders->Add( gcnew Order( "Order " + y ) );
      }
   }

   // Display a wait cursor while the TreeNodes are being created.
   ::Cursor::Current = gcnew System::Windows::Forms::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.
   myEnum = customerArray->GetEnumerator();
   while ( myEnum->MoveNext() )
   {
      Customer^ customer2 = safe_cast<Customer^>(myEnum->Current);
      treeView1->Nodes->Add( gcnew 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 = safe_cast<Order^>(myEnum->Current);
         treeView1->Nodes[ customerArray->IndexOf( customer2 ) ]->Nodes->Add( gcnew TreeNode( customer2->CustomerName + "." + order1->OrderID ) );
      }
   }
   
   // Reset the cursor to the default for all controls.
   ::Cursor::Current = Cursors::Default;
   
   // Begin repainting the TreeView.
   treeView1->EndUpdate();
}

// The basic Customer class.
public class Customer : System.Object
{
   private string custName = "";
   protected ArrayList custOrders = new ArrayList();

   public Customer(string customername)
   {
      this.custName = customername;
   }

   public string CustomerName
   {      
      get{return this.custName;}
      set{this.custName = value;}
   }

   public ArrayList CustomerOrders 
   {
      get{return this.custOrders;}
   }
} // End Customer class 

// The basic customer Order class.
public class Order : System.Object
{
   private string ordID = "";

   public Order(string orderid)
   {
      this.ordID = orderid;
   }

   public string OrderID
   {      
      get{return this.ordID;}
      set{this.ordID = value;}
   }
} // End Order class

// 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();
}

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

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


Public Class Order
   Inherits [Object]
   Private ordID As String

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

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

Remarks

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

Note

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.

Properties

Count	Gets the total number of TreeNode objects in the collection.
IsReadOnly	Gets a value indicating whether the collection is read-only.
Item[Int32]	Gets or sets the TreeNode at the specified indexed location in the collection.
Item[String]	Gets the tree node with the specified key from the collection.

Methods

Add(String, String, Int32, Int32)	Creates a tree node with the specified key, text, and images, and adds it to the collection.
Add(String, String, Int32)	Creates a tree node with the specified key, text, and image, and adds it to the collection.
Add(String, String, String, String)	Creates a tree node with the specified key, text, and images, and adds it to the collection.
Add(String, String, String)	Creates a tree node with the specified key, text, and image, and adds it to the collection.
Add(String, String)	Creates a new tree node with the specified key and text, and adds it to the collection.
Add(String)	Adds a new tree node with the specified label text to the end of the current tree node collection.
Add(TreeNode)	Adds a previously created tree node to the end of the tree node collection.
AddRange(TreeNode[])	Adds an array of previously created tree nodes to the collection.
Clear()	Removes all tree nodes from the collection.
Contains(TreeNode)	Determines whether the specified tree node is a member of the collection.
ContainsKey(String)	Determines whether the collection contains a tree node with the specified key.
CopyTo(Array, Int32)	Copies the entire collection into an existing array at a specified location within the array.
Equals(Object)	Determines whether the specified object is equal to the current object. (Inherited from Object)
Find(String, Boolean)	Finds the tree nodes with specified key, optionally searching subnodes.
GetEnumerator()	Returns an enumerator that can be used to iterate through the tree node collection.
GetHashCode()	Serves as the default hash function. (Inherited from Object)
GetType()	Gets the Type of the current instance. (Inherited from Object)
IndexOf(TreeNode)	Returns the index of the specified tree node in the collection.
IndexOfKey(String)	Returns the index of the first occurrence of a tree node with the specified key.
Insert(Int32, String, String, Int32, Int32)	Creates a tree node with the specified key, text, and images, and inserts it into the collection at the specified index.
Insert(Int32, String, String, Int32)	Creates a tree node with the specified key, text, and image, and inserts it into the collection at the specified index.
Insert(Int32, String, String, String, String)	Creates a tree node with the specified key, text, and images, and inserts it into the collection at the specified index.
Insert(Int32, String, String, String)	Creates a tree node with the specified key, text, and image, and inserts it into the collection at the specified index.
Insert(Int32, String, String)	Creates a tree node with the specified text and key, and inserts it into the collection.
Insert(Int32, String)	Creates a tree node with the specified text and inserts it at the specified index.
Insert(Int32, TreeNode)	Inserts an existing tree node into the tree node collection at the specified location.
MemberwiseClone()	Creates a shallow copy of the current Object. (Inherited from Object)
Remove(TreeNode)	Removes the specified tree node from the tree node collection.
RemoveAt(Int32)	Removes a tree node from the tree node collection at a specified index.
RemoveByKey(String)	Removes the tree node with the specified key from the collection.
ToString()	Returns a string that represents the current object. (Inherited from Object)

Explicit Interface Implementations

ICollection.IsSynchronized	Gets a value indicating whether access to the collection is synchronized (thread safe).
ICollection.SyncRoot	Gets an object that can be used to synchronize access to the collection.
IList.Add(Object)	Adds an object to the end of the tree node collection.
IList.Contains(Object)	Determines whether the specified tree node is a member of the collection.
IList.IndexOf(Object)	Returns the index of the specified tree node in the collection.
IList.Insert(Int32, Object)	Inserts an existing tree node in the tree node collection at the specified location.
IList.IsFixedSize	Gets a value indicating whether the tree node collection has a fixed size.
IList.Item[Int32]	Gets or sets the tree node at the specified index in the collection.
IList.Remove(Object)	Removes the specified tree node from the tree node collection.

Extension Methods

See also

• TreeView
• TreeNode