WinForm 树形列表（多级） 可展开，可折叠

Datagridview 实现树形列表的效果

（2020年6月9日 ：换了个gif,之前的图感觉不太好，没表现出什么）

菜单文字都做了改动，防止泄露公司的密码，毕竟签了协议的

代码中有两个字典类型

        // 记录菜单节点的层级
        Dictionary<string, int> _dictIsPMenu;
        // 是否展开
        Dictionary<string, bool> _dictPMenuExpand;

2020年6月11日更新

递归做了优化，之前的递归层级的保存有问题，最开始的if是一个层级的判断，如果想要递归多少级可以自己修改

        private void CreateTree(string pMenuId, int layer)
        {
            if (layer > 3) 
                return;
            int thisLayer = layer;
            List<M_Menu> childMenuList = allMenuList.Where(a => a.MM_PMenID == pMenuId).ToList();
            for (int i = 0; i < childMenuList.Count; i++)
            {
                menuList.Add(childMenuList[i]);
                _dictPMenuExpand.Add(childMenuList[i].MM_MenID, true);
                _dictIsPMenu.Add(childMenuList[i].MM_MenID, thisLayer);
                layer++;
                CreateTree(childMenuList[i].MM_MenID, layer);
            }
        }

2020年6月3日更新

使用了递归，可以做到无限级，但是有个问题，就是列表展示的不太好，

数据获取：

其中部分代码变成下面的样子了

            // 循环顶级节点
            for (int i = 0; i < topMenuList.Count; i++)
            {

                menuList.Add(topMenuList[i]);
                _dictIsPMenu.Add(topMenuList[i].MM_MenID, 1);
                _dictPMenuExpand.Add(topMenuList[i].MM_MenID, true);
                CreateTree(topMenuList[i].MM_MenID, 2);
            }

递归方法：这个递归有个问题就是层级有点问题，但是除了显示的层级不明确以外，其他都还好

        /// <summary>
        /// 创建树列表递归
        /// </summary>
        /// <param name="pMenuId">父菜单</param>
        /// <param name="layer">层级</param>
        private void CreateTree(string pMenuId, int layer)
        {
            List<M_Menu> childMenuList = allMenuList.Where(a => a.MM_PMenID == pMenuId).ToList();
            for (int i = 0; i < childMenuList.Count; i++)
            {
                menuList.Add(childMenuList[i]);
                _dictPMenuExpand.Add(childMenuList[i].MM_MenID, true);
                _dictIsPMenu.Add(childMenuList[i].MM_MenID, layer);
                CreateTree(childMenuList[i].MM_MenID, layer++);
            }
        }

单元格绘制代码做了一点小改动

        /// <summary>
        /// 单元格绘制
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void dgvMenuList_CellPainting(object sender, DataGridViewCellPaintingEventArgs e)
        {

            if (e.RowIndex >= 0 && dgvMenuList.Columns[e.ColumnIndex].DataPropertyName == "MM_MenName")
            {

                string menuId = this.dgvMenuList.Rows[e.RowIndex].Cells["MM_MenID"].Value.ToString();
                string menuName = this.dgvMenuList.Rows[e.RowIndex].Cells["MM_MenName"].Value.ToString();
                string pMenuId = this.dgvMenuList.Rows[e.RowIndex].Cells["MM_PMenID"].Value.ToString();
                Image img;
                Rectangle newRect;
                if (pMenuId == GuidEmpty)
                {
                    img = _dictPMenuExpand[menuId] ? Properties.Resources.tree_icon_two : Properties.Resources.tree_icon_one;
                    newRect = new Rectangle(
                        e.CellBounds.X + 3,
                        e.CellBounds.Y + e.CellBounds.Height / 2 - img.Height / 2,
                        img.Width,
                        img.Height);
                }
                else
                {
                    img = Properties.Resources.tree_icon_three;
                    // 如果有子集
                    var orgList = menuList.Where(s => s.MM_PMenID.Equals(menuId)).ToList();
                    if (orgList.Count > 0)
                    {
                        img = _dictPMenuExpand[menuId] ? Properties.Resources.tree_icon_two : Properties.Resources.tree_icon_one;
                    }
                    newRect = new Rectangle(
                        e.CellBounds.X + 3 + 10,
                        e.CellBounds.Y + e.CellBounds.Height / 2 - img.Height / 2,
                        img.Width,
                        img.Height);
                    //判断当前父节点是不是二级父节点
                    if (_dictIsPMenu[pMenuId] >= 2)
                    {
                        newRect.X += 10 * (_dictIsPMenu[pMenuId] - 1);
                    }
                }


                using (Brush gridBrush = new SolidBrush(this.dgvMenuList.GridColor),
                    backColorBrush = new SolidBrush(e.CellStyle.BackColor))
                {
                    using (Pen gridLinePen = new Pen(gridBrush, 2))
                    {
                        // 擦除单元格
                        e.Graphics.FillRectangle(backColorBrush, e.CellBounds);
                        //绘制背景色：如果选中那就用选中的蓝色背景色，否则用默认白色背景色
                        if (dgvMenuList.Rows[e.RowIndex].Cells[e.ColumnIndex].Selected)
                        {
                            e.Graphics.FillRectangle(new SolidBrush(Color.FromArgb(172, 204, 253)), e.CellBounds.X, e.CellBounds.Y, e.CellBounds.Width - 1, e.CellBounds.Height - 1);
                        }
                        else
                        {
                            e.Graphics.FillRectangle(new SolidBrush(dgvMenuList.DefaultCellStyle.BackColor), e.CellBounds.X, e.CellBounds.Y, e.CellBounds.Width - 1, e.CellBounds.Height - 1);
                        }
                        //划线
                        Point p1 = new Point(e.CellBounds.Left + e.CellBounds.Width, e.CellBounds.Top);
                        Point p2 = new Point(e.CellBounds.Left + e.CellBounds.Width, e.CellBounds.Top + e.CellBounds.Height);
                        Point p3 = new Point(e.CellBounds.Left, e.CellBounds.Top + e.CellBounds.Height);
                        Point[] ps = new Point[] { p1, p2, p3 };
                        e.Graphics.DrawLines(gridLinePen, ps);
                        //画图标
                        e.Graphics.DrawImage(img, newRect);
                        //画字符串
                        e.Graphics.DrawString(menuName.ToString(), this.Font, Brushes.Black,
                            newRect.X + 3 * 2 + img.Width, e.CellBounds.Top + Font.GetHeight(), StringFormat.GenericDefault);
                        e.Handled = true;
                    }
                }
            }
        }

单元格点击也做了改动，可以一次性展开所有子节点

        /// <summary>
        /// 单元格点击
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void dgvMenuList_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            int rowIndex = e.RowIndex;
            int colIndex = e.ColumnIndex;
            // 点中序号和标题列就返回
            if (colIndex == 0 || rowIndex < 0)
            {
                return;
            }
            string menuId = dgvMenuList.Rows[e.RowIndex].Cells["MM_MenID"].Value.ToString();
            string pMenuId = dgvMenuList.Rows[e.RowIndex].Cells["MM_PMenID"].Value.ToString();
            // 判断当前菜单ID是否是父级菜单
            if (pMenuId == GuidEmpty || (menuList.Where(s => s.MM_PMenID.Equals(menuId)).Count() > 0))
            {

                string menuName = dgvMenuList.Rows[e.RowIndex].Cells["MM_MenName"].Value.ToString();
                SetBtnShowHideState(pMenuId);
                EnergyBtnSetShow(true);
                gpObjChecks.Controls.Clear();
                bool state = !_dictPMenuExpand[menuId];
                _dictPMenuExpand[menuId] = state;
                ExpandMenu(menuId, state);
            }
            else
            {
                SetBtnShowHideState(pMenuId);
                AddCheckBoxs(menuId);
            }
        }

折叠收起递归

        /// <summary>
        /// 展开折叠递归
        /// </summary>
        /// <param name="pid">父菜单id</param>
        /// <param name="state">折叠还是收起</param>
        private void ExpandMenu(string pid, bool state)
        {
            List<M_Menu> childList = menuList.Where(s => s.MM_PMenID.Equals(pid)).ToList();
            //筛选传入的子集合
            for (int i = 0; i < childList.Count; i++)
            {
                for (int j = 0; j < dgvMenuList.RowCount; j++)
                {
                    string thisMenuId = dgvMenuList.Rows[j].Cells["MM_MenID"].Value.ToString();
                    if (thisMenuId == childList[i].MM_MenID)
                    {
                        dgvMenuList.Rows[j].Visible = state;
                    }
                }
                ExpandMenu(childList[i].MM_MenID, state);
            }

        }

---

2020年5月30日

首先需要绑定一个对应数据的泛型集合，其他的数据暂时没试过

            Dictionary<string, int>  _dictIsPMenu = new Dictionary<string, int>();
            Dictionary<string, bool> _dictPMenuExpand = new Dictionary<string, bool>();

            List<M_Menu> temp = 某个数据接口
            List<M_Menu> topMenuList = temp.Where(a => a.MM_PMenID == GuidEmpty).ToList();
            List<M_Menu> menuList = new List<M_Menu>(topMenuList.ToArray());//深拷贝
            List<M_Menu> secondMenuList;
            List<M_Menu> thirdMenuList;
            int index = 0;
            // 循环顶级节点
            for (int i = 0; i < topMenuList.Count; i++)
            {
                // 查询顶级节点下的子节点
                secondMenuList = temp.Where(a => a.MM_PMenID == topMenuList[i].MM_MenID).ToList();
                // 向数据字典添加数据
                _dictIsPMenu.Add(topMenuList[i].MM_MenID, 1);
　　　　　　　　　 // true 为默认展开
                _dictPMenuExpand.Add(topMenuList[i].MM_MenID, true);
                // 循环对应子节点
                for (int j = 0; j < secondMenuList.Count; j++)
                {
                    menuList.Insert(++index, secondMenuList[j]);
                    // 二级子节点
                    thirdMenuList = temp.Where(a => a.MM_PMenID == secondMenuList[j].MM_MenID).ToList();
                    if (thirdMenuList.Count > 0)
                    {
                        _dictIsPMenu.Add(secondMenuList[j].MM_MenID, 2);
                        _dictPMenuExpand.Add(secondMenuList[j].MM_MenID, true);
                        for (int k = 0; k < thirdMenuList.Count; k++)
                        {
                            menuList.Insert(++index, thirdMenuList[k]);
                        }
                    }
                }
                index++;
            }
            // 此数据只会查出二级子菜单的数据
            dgvMenuList.DataSource = menuList;

然后在datagridview的CellPoint  中写入画图的代码

// 判断是否是需要画图的列
if (e.RowIndex >= 0 && dgvMenuList.Columns[e.ColumnIndex].DataPropertyName == "MM_MenName")
            {

                string menuId = this.dgvMenuList.Rows[e.RowIndex].Cells["MM_MenID"].Value.ToString();
                string menuName = this.dgvMenuList.Rows[e.RowIndex].Cells["MM_MenName"].Value.ToString();
                string pMenuId = this.dgvMenuList.Rows[e.RowIndex].Cells["MM_PMenID"].Value.ToString();
                Image img;
                Rectangle newRect;
                if (_dictIsPMenu.ContainsKey(menuId))
                {
                    img = _dictPMenuExpand[menuId] ? Properties.Resources.tree_icon_two : Properties.Resources.tree_icon_one;
                    newRect = new Rectangle(
                        e.CellBounds.X + 3,
                        e.CellBounds.Y + e.CellBounds.Height / 2 - img.Height / 2,
                        img.Width,
                        img.Height);
                    //判断当前节点是不是二级父节点
                    if (_dictIsPMenu[menuId] == 2)
                    {
                        newRect.X += 10;
                    }
                }
                else
                {
                    img = Properties.Resources.tree_icon_three;
                    newRect = new Rectangle(
                        e.CellBounds.X + 3 + 10,
                        e.CellBounds.Y + e.CellBounds.Height / 2 - img.Height / 2,
                        img.Width,
                        img.Height);
                    //判断当前父节点是不是二级父节点
                    if (_dictIsPMenu[pMenuId] == 2)
                    {
                        newRect.X += 10;
                    }
                }


                using (Brush gridBrush = new SolidBrush(this.dgvMenuList.GridColor),
                    backColorBrush = new SolidBrush(e.CellStyle.BackColor))
                {
                    using (Pen gridLinePen = new Pen(gridBrush, 2))
                    {
                        // 擦除单元格
                        e.Graphics.FillRectangle(backColorBrush, e.CellBounds);
                        //绘制背景色：如果选中那就用设置的背景色，否则用默认白色背景色
                        if (dgvMenuList.Rows[e.RowIndex].Cells[e.ColumnIndex].Selected)
                        {
                            e.Graphics.FillRectangle(new SolidBrush(Color.FromArgb(172, 204, 253)), e.CellBounds.X , e.CellBounds.Y , e.CellBounds.Width - 1, e.CellBounds.Height - 1);
                        }
                        else
                        {
                            e.Graphics.FillRectangle(new SolidBrush(dgvMenuList.DefaultCellStyle.BackColor), e.CellBounds.X, e.CellBounds.Y, e.CellBounds.Width - 1, e.CellBounds.Height - 1);
                        }
                        //划线
                        Point p1 = new Point(e.CellBounds.Left + e.CellBounds.Width, e.CellBounds.Top);
                        Point p2 = new Point(e.CellBounds.Left + e.CellBounds.Width, e.CellBounds.Top + e.CellBounds.Height);
                        Point p3 = new Point(e.CellBounds.Left, e.CellBounds.Top + e.CellBounds.Height);
                        Point[] ps = new Point[] { p1, p2, p3 };
                        e.Graphics.DrawLines(gridLinePen, ps);
                        //画图标
                        e.Graphics.DrawImage(img, newRect);
                        //画字符串
                        e.Graphics.DrawString(menuName.ToString(), this.Font, Brushes.Black,
                            newRect.X + 3 * 2 + img.Width, e.CellBounds.Top + Font.GetHeight(), StringFormat.GenericDefault);
                        e.Handled = true;
                    }
                }
            }

然后实现点击展开折叠，通过datagridview 的CellClick事件，如果这个事件觉得不好也可用换一个事件，只要能获取到对应行列就行

private void dgvMenuList_CellClick(object sender, DataGridViewCellEventArgs e)
        {
            int rowIndex = e.RowIndex;
            int colIndex = e.ColumnIndex;
            // 点中序号和标题列就返回
            if (colIndex == 0 || rowIndex < 0)
            {
                return;
            }
            string menuId = dgvMenuList.Rows[e.RowIndex].Cells["MM_MenID"].Value.ToString();
            // 判断当前菜单ID是否是父级菜单
            if (_dictIsPMenu.ContainsKey(menuId))
            {
                string menuName = dgvMenuList.Rows[e.RowIndex].Cells["MM_MenName"].Value.ToString();

                gpObjChecks.Controls.Clear();
                for (int i = e.RowIndex + 1; i < dgvMenuList.RowCount; i++)
                {
                    string pMenuId = dgvMenuList.Rows[i].Cells["MM_PMenID"].Value.ToString();
                    string tempMenuId = dgvMenuList.Rows[i].Cells["MM_MenID"].Value.ToString();
                    bool state = !_dictPMenuExpand[menuId];
                    // 顶级父级
                    if (_dictIsPMenu[menuId] == 1)
                    {
                        //判断是否到下一个顶级父级菜单了
                        if (pMenuId == GuidEmpty)
                        {
                            _dictPMenuExpand[menuId] = state;

                            break;
                        }
                        dgvMenuList.Rows[i].Visible = state;
                        _dictPMenuExpand[tempMenuId] = state;
                        // 当前父菜单不是下一个顶级父菜单，但是是下一级父菜单
                        if (pMenuId != menuId)
                        {
                            dgvMenuList.Rows[i].Visible = _dictPMenuExpand[pMenuId];
                        }
                    }
                    // 次级父级
                    else
                    {
                        //判断是否到下一个次级父级菜单了
                        if (pMenuId != menuId)
                        {
                            _dictPMenuExpand[menuId] = state;
                            break;
                        }
                        else
                        {
                            dgvMenuList.Rows[i].Visible = state;
                        }
                    }
                    // 最后一行的特殊处理
                    if (i == dgvMenuList.RowCount - 1)
                    {
                        _dictPMenuExpand[menuId] = state;
                        dgvMenuList.Rows[i].Visible = state;
                    }
                }
            }
            else
            {
                string pMenuId = dgvMenuList.Rows[e.RowIndex].Cells["MM_PMenID"].Value.ToString();
                M_Menu menu = _menuBLL.GetMenu(pMenuId);

            }
        }

这篇就这些