// 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();
}

//引入命名空间
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.IO;

public class Form1 : Form
{
      private System.Windows.Forms.TreeView directoryTreeView;
     
      string substringDirectory;
       
      public Form1() {
        InitializeComponent();
        directoryTreeView.Nodes.Clear();
        
        String path = "c:\\Temp";

        directoryTreeView.Nodes.Add( path );
        PopulateTreeView(path, directoryTreeView.Nodes[ 0 ] );
      }  

      public void PopulateTreeView(string directoryValue, TreeNode parentNode )
      {
          string[] directoryArray = 
           Directory.GetDirectories( directoryValue );

          try
          {
             if ( directoryArray.Length != 0 )
             {
                foreach ( string directory in directoryArray )
                {
                  substringDirectory = directory.Substring(
                  directory.LastIndexOf( '\\' ) + 1,
                  directory.Length - directory.LastIndexOf( '\\' ) - 1 );

                  TreeNode myNode = new TreeNode( substringDirectory );

                  parentNode.Nodes.Add( myNode );

                  PopulateTreeView( directory, myNode );
               }
             }
          } catch ( UnauthorizedAccessException ) {
            parentNode.Nodes.Add( "Access denied" );
          } // end catch
      }

      private void InitializeComponent()
      {
         this.directoryTreeView = new System.Windows.Forms.TreeView();
         this.SuspendLayout();
         // 
         // directoryTreeView
         // 
         this.directoryTreeView.Location = new System.Drawing.Point(12, 77);
         this.directoryTreeView.Name = "directoryTreeView";
         this.directoryTreeView.Size = new System.Drawing.Size(284, 265);
         this.directoryTreeView.TabIndex = 0;
         // 
         // TreeViewDirectoryStructureForm
         // 
         this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
         this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
         this.ClientSize = new System.Drawing.Size(304, 354);
         this.Controls.Add(this.directoryTreeView);
         this.Name = "TreeViewDirectoryStructureForm";
         this.Text = "TreeViewDirectoryStructure";
         this.ResumeLayout(false);
         this.PerformLayout();

      }
  [STAThread]
  static void Main()
  {
    Application.EnableVisualStyles();
    Application.Run(new Form1());
  }

}