C# treeview控件部分节点添加checkbox

this.treeView1.CheckBoxes = true;
this.treeView1.ShowLines = false;
this.treeView1.DrawMode = System.Windows.Forms.TreeViewDrawMode.OwnerDrawAll;

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

private void treeView_DrawNode(object sender, DrawTreeNodeEventArgs e)
{

//隐藏节点前的checkbox
if (e.Node.ImageIndex==6)
HideCheckBox(this.treeView1, e.Node);
e.DrawDefault = true;
}

private const int TVIF_STATE = 0x8;
private const int TVIS_STATEIMAGEMASK = 0xF000;
private const int TV_FIRST = 0x1100;
private const int TVM_SETITEM = TV_FIRST + 63;
private void HideCheckBox(TreeView tvw, TreeNode node)
{

TVITEM tvi = new TVITEM();

tvi.hItem = node.Handle;

tvi.mask = TVIF_STATE;

tvi.stateMask = TVIS_STATEIMAGEMASK;

tvi.state = 0;

SendMessage(tvw.Handle, TVM_SETITEM,IntPtr.Zero, ref tvi);

}

[StructLayout(LayoutKind.Sequential, Pack = 8, CharSet = CharSet.Auto)]

private 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", CharSet = CharSet.Auto)]

private static extern IntPtr SendMessage(IntPtr hWnd, int Msg, IntPtr wParam, ref TVITEM lParam);