TreeView 节点拖拽

public Form1()
{
 InitializeComponent();
 treeView1.AllowDrop = true;
 treeView1.ItemDrag += new ItemDragEventHandler(treeView1_ItemDrag);
 treeView1.DragEnter += new DragEventHandler(treeView1_DragEnter);
 treeView1.DragDrop += new DragEventHandler(treeView1_DragDrop);
}
void treeView1_DragDrop(object sender, DragEventArgs e)
{
 TreeNode moveNode = (TreeNode)e.Data.GetData("System.Windows.Forms.TreeNode");
 //根据鼠标坐标确定要移动到的目标节点
 Point pt;
 TreeNode targeNode;
 pt = ((TreeView)(sender)).PointToClient(new Point(e.X, e.Y));
 targeNode = this.treeView1.GetNodeAt(pt);
 //如果目标节点无子节点则添加为同级节点,反之添加到下级节点的未端
 TreeNode NewMoveNode = (TreeNode)moveNode.Clone();
 if (targeNode.Nodes.Count == 0)
 {
  targeNode.Parent.Nodes.Insert(targeNode.Index, NewMoveNode);
 }
 else
 {
  targeNode.Nodes.Insert(targeNode.Nodes.Count, NewMoveNode);
 }
 //更新当前拖动的节点选择
 treeView1.SelectedNode = NewMoveNode;
 //展开目标节点,便于显示拖放效果
 targeNode.Expand();
 //移除拖放的节点
 moveNode.Remove();
}
void treeView1_DragEnter(object sender, DragEventArgs e)
{
 if (e.Data.GetDataPresent("System.Windows.Forms.TreeNode"))
 {
  e.Effect = DragDropEffects.Move;
 }
 else
 {
  e.Effect = DragDropEffects.None;
 }
}
void treeView1_ItemDrag(object sender, ItemDragEventArgs e)
{
 if (e.Button == MouseButtons.Left)
 {
  DoDragDrop(e.Item, DragDropEffects.Move);
 }
}