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TreeNode Class

Represents a node of a TreeView.

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

[SerializableAttribute]
[TypeConverterAttribute(typeof(TreeNodeConverter))]
public class TreeNode : MarshalByRefObject, ICloneable, 
	ISerializable

The TreeNode type exposes the following members.

  NameDescription
Public methodTreeNode()Initializes a new instance of the TreeNode class.
Public methodTreeNode(String)Initializes a new instance of the TreeNode class with the specified label text.
Protected methodTreeNode(SerializationInfo, StreamingContext)Initializes a new instance of the TreeNode class using the specified serialization information and context.
Public methodTreeNode(String, TreeNode[])Initializes a new instance of the TreeNode class with the specified label text and child tree nodes.
Public methodTreeNode(String, Int32, Int32)Initializes a new instance of the TreeNode class with the specified label text and images to display when the tree node is in a selected and unselected state.
Public methodTreeNode(String, Int32, Int32, TreeNode[])Initializes a new instance of the TreeNode class with the specified label text, child tree nodes, and images to display when the tree node is in a selected and unselected state.
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  NameDescription
Public propertyBackColorGets or sets the background color of the tree node.
Public propertyBoundsGets the bounds of the tree node.
Public propertyCheckedGets or sets a value indicating whether the tree node is in a checked state.
Public propertyContextMenuGets the shortcut menu that is associated with this tree node.
Public propertyContextMenuStripGets or sets the shortcut menu associated with this tree node.
Public propertyFirstNodeGets the first child tree node in the tree node collection.
Public propertyForeColorGets or sets the foreground color of the tree node.
Public propertyFullPathGets the path from the root tree node to the current tree node.
Public propertyHandleGets the handle of the tree node.
Public propertyImageIndexGets or sets the image list index value of the image displayed when the tree node is in the unselected state.
Public propertyImageKeyGets or sets the key for the image associated with this tree node when the node is in an unselected state.
Public propertyIndexGets the position of the tree node in the tree node collection.
Public propertyIsEditingGets a value indicating whether the tree node is in an editable state.
Public propertyIsExpandedGets a value indicating whether the tree node is in the expanded state.
Public propertyIsSelectedGets a value indicating whether the tree node is in the selected state.
Public propertyIsVisibleGets a value indicating whether the tree node is visible or partially visible.
Public propertyLastNodeGets the last child tree node.
Public propertyLevelGets the zero-based depth of the tree node in the TreeView control.
Public propertyNameGets or sets the name of the tree node.
Public propertyNextNodeGets the next sibling tree node.
Public propertyNextVisibleNodeGets the next visible tree node.
Public propertyNodeFontGets or sets the font that is used to display the text on the tree node label.
Public propertyNodesGets the collection of TreeNode objects assigned to the current tree node.
Public propertyParentGets the parent tree node of the current tree node.
Public propertyPrevNodeGets the previous sibling tree node.
Public propertyPrevVisibleNodeGets the previous visible tree node.
Public propertySelectedImageIndexGets or sets the image list index value of the image that is displayed when the tree node is in the selected state.
Public propertySelectedImageKeyGets or sets the key of the image displayed in the tree node when it is in a selected state.
Public propertyStateImageIndexGets or sets the index of the image that is used to indicate the state of the TreeNode when the parent TreeView has its CheckBoxes property set to false.
Public propertyStateImageKeyGets or sets the key of the image that is used to indicate the state of the TreeNode when the parent TreeView has its CheckBoxes property set to false.
Public propertyTagGets or sets the object that contains data about the tree node.
Public propertyTextGets or sets the text displayed in the label of the tree node.
Public propertyToolTipTextGets or sets the text that appears when the mouse pointer hovers over a TreeNode.
Public propertyTreeViewGets the parent tree view that the tree node is assigned to.
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  NameDescription
Public methodBeginEditInitiates the editing of the tree node label.
Public methodCloneCopies the tree node and the entire subtree rooted at this tree node.
Public methodCollapse()Collapses the tree node.
Public methodCollapse(Boolean)Collapses the TreeNode and optionally collapses its children.
Public methodCreateObjRefCreates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject.)
Protected methodDeserializeLoads the state of the TreeNode from the specified SerializationInfo.
Public methodEndEditEnds the editing of the tree node label.
Public methodEnsureVisibleEnsures that the tree node is visible, expanding tree nodes and scrolling the tree view control as necessary.
Public methodEquals(Object)Determines whether the specified object is equal to the current object. (Inherited from Object.)
Public methodExpandExpands the tree node.
Public methodExpandAllExpands all the child tree nodes.
Protected methodFinalizeAllows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.)
Public methodStatic memberFromHandleReturns the tree node with the specified handle and assigned to the specified tree view control.
Public methodGetHashCodeServes as the default hash function. (Inherited from Object.)
Public methodGetLifetimeServiceRetrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
Public methodGetNodeCountReturns the number of child tree nodes.
Public methodGetTypeGets the Type of the current instance. (Inherited from Object.)
Public methodInitializeLifetimeServiceObtains a lifetime service object to control the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
Protected methodMemberwiseClone()Creates a shallow copy of the current Object. (Inherited from Object.)
Protected methodMemberwiseClone(Boolean)Creates a shallow copy of the current MarshalByRefObject object. (Inherited from MarshalByRefObject.)
Public methodRemoveRemoves the current tree node from the tree view control.
Protected methodSerializeSaves the state of the TreeNode to the specified SerializationInfo.
Public methodToggleToggles the tree node to either the expanded or collapsed state.
Public methodToStringReturns a string that represents the current object. (Overrides Object.ToString().)
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  NameDescription
Explicit interface implemetationPrivate methodISerializable.GetObjectDataPopulates a serialization information object with the data needed to serialize the TreeNode.
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The Nodes collection holds all the child TreeNode objects assigned to the current TreeNode. You can add, remove, or clone a TreeNode; when you do this, all child tree nodes are added, removed, or cloned. Each TreeNode can contain a collection of other TreeNode objects. This can make it difficult to determine where you are in the TreeView when iterating through the collection. To determine your location in a tree structure, use the FullPath property. The FullPath string can be parsed using the PathSeparator string value to determine where a TreeNode label begins and ends.

The TreeNode label is set by setting the Text property explicitly. The alternative is to create the tree node using one of the TreeNode constructors that has a string parameter that represents the Text property. The label is displayed next to the TreeNode image, if one is displayed.

To display images next to the tree nodes, assign an ImageList to the ImageList property of the parent TreeView control and assign an Image by referencing its index value in the ImageList property. Set the ImageIndex property to the index value of the Image you want to display when the TreeNode is in an unselected state. Likewise, set the SelectedImageIndex property to the index value of the Image you want to display when the TreeNode is selected.

Selecting specific tree nodes and iterating through the Nodes collection can be achieved by using the following property values: FirstNode, LastNode, NextNode, PrevNode, NextVisibleNode, PrevVisibleNode. Assign the TreeNode returned by one of aforementioned properties to the TreeView.SelectedNode property to select that tree node in the TreeView control.

Tree nodes can be expanded to display the next level of child tree nodes. The user can expand the TreeNode by pressing the plus (+) button next to the TreeNode, if one is displayed, or you can expand the TreeNode by calling the Expand method. To expand all child tree node levels in the Nodes collection, call the ExpandAll method. You can collapse the child TreeNode level by calling the Collapse method, or the user can press the minus (-) button next to the TreeNode, if one is displayed. You can also call the Toggle method to alternate the TreeNode between the expanded and collapsed states.

Tree nodes can optionally display a check box. To display the check boxes, set the CheckBoxes property of the TreeView to true. The Checked property is set to true for tree nodes that are in a checked state.

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. 
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();
}

.NET Framework

Supported in: 4.6, 4, 3.5, 3.0, 2.0, 1.1, 1.0

.NET Framework Client Profile

Supported in: 4, 3.5 SP1

Windows 8.1, Windows Server 2012 R2, Windows 8, Windows Server 2012, Windows 7, Windows Vista SP2, Windows Server 2008 (Server Core Role not supported), Windows Server 2008 R2 (Server Core Role supported with SP1 or later; Itanium not supported)

The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.

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