customized checkbox in child node and no checkbox in parent node in a treeview

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Text;
using System.Windows.Forms;
using System.Xml;
using System.Drawing.Drawing2D;
using System.Runtime.InteropServices;

namespace WindowsApplication2
{
    public partial class Form2 : Form
    {

        public const int TVIF_STATE = 0x8;
        public const int TVIS_STATEIMAGEMASK = 0xF000;
        public const int TV_FIRST = 0x1100;
        public const int TVM_SETITEM = TV_FIRST + 63;

        [StructLayout(LayoutKind.Sequential)]
        public struct TVITEM
        {
            public int mask;
            public IntPtr hItem;
            public int state;
            public int stateMask;
            [MarshalAs(UnmanagedType.LPTStr)]
            public string lpszText;
            public int cchTextMax;
            public int iImage;
            public int iSelectedImage;
            public int cChildren;
            public IntPtr lParam;
        }

        [DllImport("User32.dll")]
        public static extern int SendMessage (IntPtr hwnd, int msg, IntPtr wParam, ref TVITEM lParam);

        private void TreeNode_SetStateImageIndex(TreeNode node, int index)
        {
            TVITEM tvi = new TVITEM();
            tvi.hItem = node.Handle;
            tvi.mask = TVIF_STATE;
            tvi.stateMask = TVIS_STATEIMAGEMASK;
            tvi.state = index << 12;
            SendMessage(node.TreeView.Handle, TVM_SETITEM, IntPtr.Zero, ref tvi);
        }
        public Form2()
        {
            InitializeComponent();
            this.treeView1.CheckBoxes = true;
            this.treeView1.ShowLines = true;
            this.treeView1.ShowPlusMinus = true;
            this.treeView1.ShowNodeToolTips = true;
            this.treeView1.ShowRootLines = true;
            treeView1.ItemHeight = 25;
            

            this.treeView1.DrawMode = System.Windows.Forms.TreeViewDrawMode.OwnerDrawAll;

            this.treeView1.DrawNode += new System.Windows.Forms.DrawTreeNodeEventHandler(this.treeView_DrawNode);

            for (int i = 0; i < 3; i++)
            {
                this.treeView1.Nodes.Add(string.Format("First level {0}", i));
                for (int j = 0; j < 2; j++)
                {
                    this.treeView1.Nodes[i].Nodes.Add(string.Format("Second level {0}", j));
                    for (int k = 0; k < 2; k++)
                    {
                        this.treeView1.Nodes[i].Nodes[j].Nodes.Add(string.Format("Third level {0}", k));
                    }
                }
            }           
        }

        private void treeView_DrawNode(object sender, DrawTreeNodeEventArgs e)
        {

            Color backColor, foreColor;

            if ((e.State & TreeNodeStates.Selected) == TreeNodeStates.Selected)
            {
                backColor = SystemColors.Highlight;
                foreColor = SystemColors.HighlightText;

            }

            else if ((e.State & TreeNodeStates.Hot) == TreeNodeStates.Hot)
            {

                backColor = SystemColors.HotTrack;
                foreColor = SystemColors.HighlightText;

            }

            else
            {
                backColor = e.Node.BackColor;
                foreColor = e.Node.ForeColor;
            }

            using (SolidBrush brush = new SolidBrush(backColor))
            {

                e.Graphics.FillRectangle(brush, e.Node.Bounds);
                //e.Graphics.FillPath(brush, GraphicsPath p);

            }

            TextRenderer.DrawText(e.Graphics, e.Node.Text, this.treeView1.Font, e.Node.Bounds, foreColor, backColor);

            if ((e.State & TreeNodeStates.Focused) == TreeNodeStates.Focused)
            {

                ControlPaint.DrawFocusRectangle(e.Graphics, e.Node.Bounds, foreColor, backColor);

            }
            if (HasParent(e.Node) == false)
            {
                TreeNode_SetStateImageIndex(e.Node, 0);
            }

            e.DrawDefault = true;
        }


        private static bool HasChild(TreeNode node)
        {
            int nodeCount = 0;
            foreach (TreeNode x in node.Nodes)
                nodeCount++;
            if (nodeCount != 0)
                return true;
            else
                return false;

        }

        private static bool HasParent(TreeNode node)
        {
            if (node.Parent == null)
                return false;
            else
                return true;
        }


    }
}

 

ref:http://social.msdn.microsoft.com/Forums/en-US/csharplanguage/thread/4992c9ef-59cc-41ec-bae0-43b7e335560d

http://groups.google.com/group/microsoft.public.dotnet.framework.windowsforms/msg/0a0b6b7c0571018c?hl=en