首先把树形控件和面板的属性AllowDrop改为True。
树形控件的ItemDrag事件：
private void treeView1_ItemDrag(object sender, ItemDragEventArgs e)
{
if (e.Button == MouseButtons.Left)
   {
      DoDragDrop(e.Item, DragDropEffects.Move);
      isMouseDown = true;
    }
 }
树形控件的DragEnter事件：
private void treeView1_DragEnter(object sender, DragEventArgs e)
{
if (isMouseDown)
  {
      e.Effect = DragDropEffects.Move;
   }
else
   {
       e.Effect = DragDropEffects.None;
   }
}
树形控件的DragDrop事件
private void treeView1_DragDrop(object sender, DragEventArgs e)
        {
            TreeNode moveNode = (TreeNode)e.Data.GetData("System.Windows.Forms.TreeNode");
//根¨´据Y鼠º¨®标À¨º坐Á?标À¨º确¨¡¤定¡§要°a移°?动¡¥到Ì?的Ì?目?标À¨º节¨²点Ì?  
            Point pt;
            TreeNode targeNode;
            pt = ((TreeView)(sender)).PointToClient(new Point(e.X, e.Y));
            targeNode = this.treeView1.GetNodeAt(pt);
        }
Panel2面板（容器）控件的DragEnter事件
private void panel2_DragEnter(object sender, DragEventArgs e)
        {
if (isMouseDown)
                e.Effect = DragDropEffects.Move;
else
                e.Effect = DragDropEffects.None;
        }
PnlView面板（浏览区域）的DragEnter事件
private void PnlView_DragEnter(object sender, DragEventArgs e)
        { if (isMouseDown)
                e.Effect = DragDropEffects.Move;
else
                e.Effect = DragDropEffects.None;
        }
PnlView面板（浏览区域）的DragDrop事件
private void PnlView_DragDrop(object sender, DragEventArgs e)
{
    Position.X = e.X;
    Position.Y = e.Y;
    Position = PnlView.PointToClient(Position);
    GetPointWindow(Position, ViewCount);//获取停留的窗口PS：这个自己定义。
 }