private static DataSet objSet = new DataSet();

        //动态构造树-这里支持5级
        public static void SetTrees(TreeView node)
        {
            objSet = Data.GetUnite.GetUnites();
            if (objSet != null)
            {
                if (objSet.Tables[0].Rows.Count != 0)
                {
                    //1级
                    for (int i = 0; i < objSet.Tables[0].Rows.Count; i++)
                    {
                        node.Nodes.Add(objSet.Tables[0].Rows[i][1].ToString());
                    }
                    //2级
                    for (int i = 0; i < node.Nodes.Count; i++)
                    {
                        string nodeDir = gettree(node.Nodes[i]);
                        objSet.Clear();
                        objSet = Data.GetUnite.GetUnites1(nodeDir);

                        for (int j = 0; j < objSet.Tables[0].Rows.Count; j++)
                        {
                            node.Nodes[i].Nodes.Add(objSet.Tables[0].Rows[j][1].ToString());
                        }
                        node.Nodes[i].Expand();
                    }
                    //3级
                    for (int i = 0; i < node.Nodes.Count; i++)
                    {
                        for (int k = 0; k < node.Nodes[i].Nodes.Count; k++)
                        {
                            string nodeDir2 = gettree(node.Nodes[i].Nodes[k]);
                            objSet.Clear();
                            objSet = Data.GetUnite.GetUnites1(nodeDir2);
                            for (int j = 0; j < objSet.Tables[0].Rows.Count; j++)
                            {
                                node.Nodes[i].Nodes[k].Nodes.Add(objSet.Tables[0].Rows[j][1].ToString());
                                node.Nodes[i].Nodes[k].Expand();
                            }
                        }
                    }
                    //4级
                    for (int i = 0; i < node.Nodes.Count; i++)
                    {
                        for (int k = 0; k < node.Nodes[i].Nodes.Count; k++)
                        {
                            for (int g = 0; g < node.Nodes[i].Nodes[k].Nodes.Count; g++)
                            {
                                string nodeDir2 = gettree(node.Nodes[i].Nodes[k].Nodes[g]);
                                objSet.Clear();
                                objSet = Data.GetUnite.GetUnites1(nodeDir2);
                                for (int j = 0; j < objSet.Tables[0].Rows.Count; j++)
                                {
                                    node.Nodes[i].Nodes[k].Nodes[g].Nodes.Add(objSet.Tables[0].Rows[j][1].ToString());
                                    node.Nodes[i].Nodes[k].Nodes[g].Expand();
                                }
                            }
                        }
                    }
                    //5级
                    for (int i = 0; i < node.Nodes.Count; i++)
                    {
                        for (int k = 0; k < node.Nodes[i].Nodes.Count; k++)
                        {
                            for (int g = 0; g < node.Nodes[i].Nodes[k].Nodes.Count; g++)
                            {
                                for (int h = 0; h < node.Nodes[i].Nodes[k].Nodes[g].Nodes.Count; h++)
                                {
                                    string nodeDir2 = gettree(node.Nodes[i].Nodes[k].Nodes[g].Nodes[h]);
                                    objSet.Clear();
                                    objSet = Data.GetUnite.GetUnites1(nodeDir2);
                                    for (int j = 0; j < objSet.Tables[0].Rows.Count; j++)
                                    {
                                        node.Nodes[i].Nodes[k].Nodes[g].Nodes[h].Nodes.Add(objSet.Tables[0].Rows[j][1].ToString());
                                        node.Nodes[i].Nodes[k].Nodes[g].Nodes[h].Expand();
                                    }
                                }
                            }
                        }
                    }
                }
            }
        }

        //利用递归取得节点的路径
        private static string gettree(TreeNode nood)
        {
            if (nood.Parent == null)
            {
                return nood.Text;
            }
            return Path.Combine(gettree(nood.Parent), nood.Text);
        }

         //树节点拖动操作
        public static void TreeDrop(TreeView treeView3, DragEventArgs e)
        {
            TreeNode newNode;

            if (e.Data.GetDataPresent("System.Windows.Forms.TreeNode", false))
            {

                Point pt;

                TreeNode destinationNode;

                pt = treeView3.PointToClient(new Point(e.X, e.Y));

                destinationNode = treeView3.GetNodeAt(pt);

                newNode = (TreeNode)e.Data.GetData("System.Windows.Forms.TreeNode");
                //最上级不能拖动到下级或者同级
                if (newNode.Parent == null || newNode.Parent.Parent == null )
                {
                    //集团总部\第二研究院\1所\安全保卫处\sss
                }
                else
                {
                    string[] FullPath = destinationNode.FullPath.ToString().Split(new string[1] { "\\" }, StringSplitOptions.None);
                   //超过最大级限不能拖动添加
                    if (!destinationNode.Equals(newNode)&& FullPath.Length<5)
                    {

                        //destinationNode.Nodes.Add(newNode.Clone());

                        destinationNode.Nodes.Add((TreeNode)newNode.Clone());

                        destinationNode.Expand();

                        //Remove original node

                        newNode.Remove();

                    }

                    string nodeDIR = gettree(destinationNode);
                    //MessageBox.Show(nodeDIR + "\\" + newNode.Text.ToString());
                    Data.GetUnite.UpdataPernt(newNode.Text.ToString().Trim(), nodeDIR);
                }
            }
        }