TreeView 的 TreeNode拖拉

Question

（C#）怎么在TreeView中 实现TreeNode的拖拉 来改变树的结构

Answer 1

代码有点长，两年前写的(win form)：

        #region 增加拖放功能
        /// <summary>
        /// 拖拽处理
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void tvwFunctions_ItemDrag(object sender, ItemDragEventArgs e)
        {
            DoDragDrop(e.Item, DragDropEffects.Move);

        }

        /// <summary>
        /// 拖放处理
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void tvwFunctions_DragEnter(object sender, DragEventArgs e)
        {
            // 如果拖放的是TreeNode对象，显示拖放的效果
            if (e.Data.GetDataPresent("System.Windows.Forms.TreeNode", true))
            {
                e.Effect = DragDropEffects.Move;
            }
            else
            {
                // 如果不是TreeNode对象，阻止拖放
                e.Effect = DragDropEffects.None;
            }
        }
        /// <summary>
        /// 拖动放下时，将拖动的节点放到目标功能点下。
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void tvwFunctions_DragDrop(object sender, DragEventArgs e)
        {
            //不是树节点则返回
            if (!(e.Data.GetDataPresent(typeof(TreeNode)))) return;

            // 目标节点的位置
            Point pt = this.tvwFunctions.PointToClient(new Point(e.X, e.Y));

            // 获取目标节点
            TreeNode nodeTo = this.tvwFunctions.GetNodeAt(pt);

            if (nodeTo == null) return;

            TreeNode nodeFrom = (TreeNode)e.Data.GetData(typeof(TreeNode));

            if (LY.TEC.Framework.Common.Client.BaseForm.MessageBoxShow((IWin32Window)this, "是否将拖动的功能点" + nodeFrom.Text + "移到该功能点" + nodeTo.Text +
                "下?", "提示确认", MessageBoxButtons.YesNo,1) != DialogResult.Yes)
            {
                return;
            }

            MoveNode(nodeFrom, nodeTo);

        }

        private TreeNode mLastTreeNode;
        /// <summary>
        /// 拖动中处理
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void tvwFunctions_DragOver(object sender, DragEventArgs e)
        {
            // 如果拖放的不是TreeNode对象
            if (!e.Data.GetDataPresent("System.Windows.Forms.TreeNode", true))
            {
                e.Effect = DragDropEffects.None;
                return;
            }

            // 目标节点的位置
            Point pt = this.tvwFunctions.PointToClient(new Point(e.X, e.Y));

            // 获取目标节点
            TreeNode targetNode = this.tvwFunctions.GetNodeAt(pt);

            // 拖动中的节点
            TreeNode dropNode = e.Data.GetData("System.Windows.Forms.TreeNode", true) as TreeNode;

            // 判断放置的目标节点是否就是本身开始拖的节点或者是根节点(模块节点不运行投放)
            // 如果是，不处理
            if (targetNode == dropNode || targetNode == null || dropNode.Parent == null)
            {
                e.Effect = DragDropEffects.None;
                return;
            }

            // 如果目标对象就是自己的父节点，说明位置没有变，无需处理
            if (dropNode.Parent == targetNode)
            {
                e.Effect = DragDropEffects.None;
                return;
            }

            // 父亲节点不能拖放到儿子节点上
            if (IsParent(targetNode, dropNode))
            {
                e.Effect = DragDropEffects.None;
                return;
            }

            // 功能菜单(可认为是叶子节点)不允许放置

            // 上一个鼠标Over过的节点字体颜色回原
            if (this.mLastTreeNode != null)
            {
                this.mLastTreeNode.ForeColor = System.Drawing.Color.Black;
            }
            // 目标节点颜色变兰以特出显示
            this.mLastTreeNode = targetNode;
            this.mLastTreeNode.ForeColor = System.Drawing.Color.Blue;

            // 其他目标节点允许拖放
            e.Effect = DragDropEffects.Move;
        }
        /// <summary>
        /// 处理功能移动。
        /// </summary>
        /// <param name="nodeFrom">从那个功能节点</param>
        /// <param name="nodeTo">到哪个功能节点</param>
        private void MoveNode(TreeNode nodeFrom, TreeNode nodeTo)
        {
            DataRow drFrom = nodeFrom.Tag as DataRow;

            DataRow drTo = nodeTo.Tag as DataRow;

            string[] sColumns = new string[] { "LAST_UPDATED_DATE", "PRIV_ID","PARENT_PRIV_ID" };

            DataTable dtPriv = mDataAccess.DuplicateDataTable("SYS_PRIV",sColumns);

            DataRow dr = dtPriv.NewRow();

            dr["LAST_UPDATED_DATE"] = drFrom["LAST_UPDATED_DATE"];
            dr["PARENT_PRIV_ID"] = drTo["PRIV_ID"];
            dr["PRIV_ID"] = drFrom["PRIV_ID"];

            dtPriv.Rows.Add(dr);

            dtPriv.AcceptChanges();

            dr.SetModified();

            DataTable dtNew = functionService.SaveFunction(dtPriv);

            nodeFrom.Parent.Nodes.Remove(nodeFrom);
            ShowSubNode(nodeTo);
            nodeTo.Nodes.Add(nodeFrom);

            //移动后修改界面数据，以便下次修改。
            drFrom["LAST_UPDATED_DATE"] = dtNew.Rows[0]["LAST_UPDATED_DATE"];
            drFrom["PARENT_PRIV_ID"] = dtNew.Rows[0]["PARENT_PRIV_ID"];
        }

        /// <summary>
        /// 判断两个节点是否为父子
        /// </summary>
        /// <param name="nodeParent">父节点</param>
        /// <param name="nodeSon">子节点</param>
        /// <returns>是否父子</returns>
        private bool IsParent(TreeNode nodeParent, TreeNode nodeSon)
        {
            if (nodeParent.Nodes.Count < 1) return false;

            if (nodeSon.Parent == nodeParent) return true;

            return false;
        }
        #endregion;

Answer 2

3KU Very Much