（六十五）c#Winform自定义控件-思维导图/组织架构图（工业）-HZHControls

官网

http://www.hzhcontrols.com

前提

入行已经7,8年了，一直想做一套漂亮点的自定义控件，于是就有了本系列文章。

GitHub：https://github.com/kwwwvagaa/NetWinformControl

码云：https://gitee.com/kwwwvagaa/net_winform_custom_control.git

如果觉得写的还行，请点个 star 支持一下吧

欢迎前来交流探讨： 企鹅群568015492 

麻烦博客下方点个【推荐】，谢谢

NuGet

Install-Package HZH_Controls

目录

https://www.cnblogs.com/bfyx/p/11364884.html

用处及效果

准备工作

依然是用GDI+画的，不懂的可以先百度一下

开始

添加一个实体类，用以记录数据源节点信息

 public class MindMappingItemEntity
    {
        /// <summary>
        /// Gets or sets the identifier.
        /// </summary>
        /// <value>The identifier.</value>
        public string ID { get; set; }
        private string _text;
        /// <summary>
        /// Gets or sets the text.
        /// </summary>
        /// <value>The text.</value>
        public string Text
        {
            get { return _text; }
            set
            {
                _text = value;
                ResetSize();
            }
        }
        /// <summary>
        /// Gets or sets the data source.
        /// </summary>
        /// <value>The data source.</value>
        public object DataSource { get; set; }
        /// <summary>
        /// The childrens
        /// </summary>
        private MindMappingItemEntity[] _Childrens;
        /// <summary>
        /// Gets or sets the childrens.
        /// </summary>
        /// <value>The childrens.</value>
        public MindMappingItemEntity[] Childrens
        {
            get { return _Childrens; }
            set
            {
                _Childrens = value;
                if (value != null && value.Length > 0)
                {
                    value.ToList().ForEach(p => { if (p != null) { p.ParentItem = this; } });
                }
            }
        }
        /// <summary>
        /// The back color
        /// </summary>
        private Color backColor = Color.Transparent;

        /// <summary>
        /// Gets or sets the color of the back.
        /// </summary>
        /// <value>The color of the back.</value>
        public Color BackColor
        {
            get { return backColor; }
            set { backColor = value; }
        }

        private Font font = new Font("微软雅黑", 10);

        public Font Font
        {
            get { return font; }
            set
            {
                font = value;
                ResetSize();
            }
        }

        /// <summary>
        /// The fore color
        /// </summary>
        private Color foreColor = Color.Black;

        /// <summary>
        /// Gets or sets the color of the fore.
        /// </summary>
        /// <value>The color of the fore.</value>
        public Color ForeColor
        {
            get { return foreColor; }
            set { foreColor = value; }
        }
        private bool _IsExpansion = false;
        /// <summary>
        /// Gets or sets a value indicating whether the instance is expanded.
        /// </summary>
        /// <value><c>true</c> if this instance is expansion; otherwise, <c>false</c>.</value>
        public bool IsExpansion
        {
            get
            {
                return _IsExpansion;
            }
            set
            {
                if (value == _IsExpansion)
                    return;
                _IsExpansion = value;
                if (!value)
                {
                    _Childrens.ToList().ForEach(p => { if (p != null) { p.IsExpansion = false; } });
                }

            }
        }

        /// <summary>
        /// Gets the parent item.
        /// </summary>
        /// <value>The parent item.</value>
        public MindMappingItemEntity ParentItem { get; private set; }
        /// <summary>
        /// Gets all childrens maximum show count.
        /// </summary>
        /// <value>All childrens maximum show count.</value>
        public int AllChildrensMaxShowHeight { get { return GetAllChildrensMaxShowHeight(); } }
        /// <summary>
        /// Gets the maximum level.
        /// </summary>
        /// <value>The maximum level.</value>
        public int AllChildrensMaxShowWidth { get { return GetAllChildrensMaxShowWidth(); } }

        /// <summary>
        /// Gets all childrens maximum show count.
        /// </summary>
        /// <returns>System.Int32.</returns>
        private int GetAllChildrensMaxShowHeight()
        {
            if (!_IsExpansion || _Childrens == null || _Childrens.Length <= 0)
                return ItemHeight + 10;
            else
            {
                return _Childrens.Sum(p => p == null ? 0 : p.AllChildrensMaxShowHeight);
            }
        }
        /// <summary>
        /// Gets the maximum level.
        /// </summary>
        /// <returns>System.Int32.</returns>
        private int GetAllChildrensMaxShowWidth()
        {
            if (!_IsExpansion || _Childrens == null || _Childrens.Length <= 0)
                return ItemWidth + 50;
            else
            {
                return 1 + _Childrens.Max(p => p == null ? 0 : p.AllChildrensMaxShowWidth);
            }
        }
        /// <summary>
        /// Gets or sets the working rectangle.
        /// </summary>
        /// <value>The working rectangle.</value>
        internal RectangleF WorkingRectangle { get; set; }
        /// <summary>
        /// Gets or sets the draw rectangle.
        /// </summary>
        /// <value>The draw rectangle.</value>
        internal RectangleF DrawRectangle { get; set; }
        /// <summary>
        /// Gets or sets the expansion rectangle.
        /// </summary>
        /// <value>The expansion rectangle.</value>
        internal RectangleF ExpansionRectangle { get; set; }
        /// <summary>
        /// Gets the height of the item.
        /// </summary>
        /// <value>The height of the item.</value>
        private int ItemHeight { private get; private set; }
        /// <summary>
        /// Gets the width of the item.
        /// </summary>
        /// <value>The width of the item.</value>
        private int ItemWidth { private get; private set; }
        /// <summary>
        /// Resets the size.
        /// </summary>
        private void ResetSize()
        {
            string _t = _text;
            if (string.IsNullOrEmpty(_t))
            {
                _t = "aaaa";
            }
            Bitmap bit = new Bitmap(1, 1);
            var g = Graphics.FromImage(bit);
            var size = g.MeasureString(_t, font);
            g.Dispose();
            bit.Dispose();
            ItemHeight = (int)size.Height;
            ItemWidth = (int)size.Width;
        }
    }

主要属性说明：

Text：显示文字

Childrens：子节点信息

BackColor：节点颜色

IsExpansion：是否展开子节点

ParentItem：父级节点

AllChildrensMaxShowHeight：该节点包含所有子节点需要显示的高度，通过私有函数GetAllChildrensMaxShowHeight()返回结果

AllChildrensMaxShowWidth：该节点包含所有子节点需要显示的宽度，通过私有函数GetAllChildrensMaxShowWidth()返回结果

WorkingRectangle：该节点以及所有子节点的工作区域

DrawRectangle：该节点的绘制区域

ExpansionRectangle：展开折叠按钮的绘制区域

ItemHeight：该节点的高度

ItemWidth：该节点的宽度

主要函数说明：

GetAllChildrensMaxShowHeight：获取当前节点及所有子节点需要的最大高度

GetAllChildrensMaxShowWidth：获取当前节点及所有子节点需要的最大宽度

ResetSize：当文本和字体改变时重新计算宽高

添加一个类UCMindMapping，继承UserControl

添加一些属性

 /// <summary>
        /// The line color
        /// </summary>
        private Color lineColor = Color.Black;

        /// <summary>
        /// Gets or sets the color of the line.
        /// </summary>
        /// <value>The color of the line.</value>
        [Description("线条颜色"), Category("自定义")]
        public Color LineColor
        {
            get { return lineColor; }
            set
            {
                lineColor = value;
                Refresh();
            }
        }
        /// <summary>
        /// The split width
        /// </summary>
        private int splitWidth = 50;
        // private int itemHeight = 20;
        /// <summary>
        /// The padding
        /// </summary>
        private int padding = 20;

        /// <summary>
        /// The m rect working
        /// </summary>
        Rectangle m_rectWorking = Rectangle.Empty;
        /// <summary>
        /// Occurs when [item clicked].
        /// </summary>
        public event EventHandler ItemClicked;
        /// <summary>
        /// The data source
        /// </summary>
        private MindMappingItemEntity dataSource;
        /// <summary>
        /// Gets or sets the data source.
        /// </summary>
        /// <value>The data source.</value>
        [Description("数据源"), Category("自定义")]
        public MindMappingItemEntity DataSource
        {
            get { return dataSource; }
            set
            {
                dataSource = value;

                ResetSize();
            }
        }

一个辅助函数，用以在大小过数据改变时计算工作区域和位置

 /// <summary>
        /// 重置大小
        /// </summary>
        private void ResetSize()
        {
            if (this.Parent == null)
                return;
            try
            {
                ControlHelper.FreezeControl(this, true);
                if (dataSource == null)
                {
                    m_rectWorking = Rectangle.Empty;
                    this.Size = this.Parent.Size;
                }
                else
                {
                    int intWidth = dataSource.AllChildrensMaxShowWidth;
                    int intHeight = dataSource.AllChildrensMaxShowHeight;
                    this.Width = intWidth + padding * 2;
                    this.Height = intHeight + padding * 2;
                    if (this.Width < this.Parent.Width)
                        this.Width = this.Parent.Width;
                    m_rectWorking = new Rectangle(padding, padding, intWidth, intHeight);
                    if (this.Height > this.Parent.Height)
                    {
                        //this.Location = new Point(0, 0);
                    }
                    else
                        this.Location = new Point(0, (this.Parent.Height - this.Height) / 2);
                }
            }
            finally
            {
                ControlHelper.FreezeControl(this, false);
            }
        }

重绘

 /// <summary>
        /// 引发 <see cref="E:System.Windows.Forms.Control.Paint" /> 事件。
        /// </summary>
        /// <param name="e">包含事件数据的 <see cref="T:System.Windows.Forms.PaintEventArgs" />。</param>
        protected override void OnPaint(PaintEventArgs e)
        {
            try
            {
                base.OnPaint(e);
                if (m_rectWorking == Rectangle.Empty || m_rectWorking == null)
                    return;
                var g = e.Graphics;
                g.SetGDIHigh();

                int intHeight = dataSource.AllChildrensMaxShowHeight;
                dataSource.WorkingRectangle = new RectangleF(m_rectWorking.Left, m_rectWorking.Top + (m_rectWorking.Height - intHeight) / 2, m_rectWorking.Width, intHeight);

                DrawItem(dataSource, g);
            }
            catch (Exception exc)
            {
                MessageBox.Show(exc.ToString(), "错误");
            }
        }

/// <summary>
        /// 画节点
        /// </summary>
        /// <param name="item">The item.</param>
        /// <param name="g">The g.</param>
        private void DrawItem(MindMappingItemEntity item, Graphics g)
        {
            //节点
            var size = g.MeasureString(item.Text, item.Font);
            item.DrawRectangle = new RectangleF(item.WorkingRectangle.Left + 2, item.WorkingRectangle.Top + (item.WorkingRectangle.Height - size.Height) / 2 + 2, size.Width + 4, size.Height + 4);
            GraphicsPath drawPath = item.DrawRectangle.CreateRoundedRectanglePath(5);
            g.FillPath(new SolidBrush(item.BackColor), drawPath);
            g.DrawString(item.Text, item.Font, new SolidBrush(item.ForeColor), item.DrawRectangle.Location.X + 2, item.DrawRectangle.Location.Y + 2);
            //子节点
            if (item.Childrens != null && item.IsExpansion)
            {
                for (int i = 0; i < item.Childrens.Length; i++)
                {
                    var child = item.Childrens[i];
                    if (i == 0)
                    {
                        child.WorkingRectangle = new RectangleF(item.DrawRectangle.Right + splitWidth, item.WorkingRectangle.Top, item.WorkingRectangle.Width - (item.DrawRectangle.Width + splitWidth), child.AllChildrensMaxShowHeight);
                    }
                    else
                    {
                        child.WorkingRectangle = new RectangleF(item.DrawRectangle.Right + splitWidth, item.Childrens[i - 1].WorkingRectangle.Bottom, item.WorkingRectangle.Width - (item.DrawRectangle.Width + splitWidth), child.AllChildrensMaxShowHeight);
                    }
                    DrawItem(child, g);
                }
            }
            //连线
            if (item.ParentItem != null)
            {
                g.DrawLines(new Pen(new SolidBrush(lineColor), 1), new PointF[] 
                { 
                    new PointF(item.ParentItem.DrawRectangle.Right,item.ParentItem.DrawRectangle.Top+item.ParentItem.DrawRectangle.Height/2),
                    new PointF(item.ParentItem.DrawRectangle.Right+12,item.ParentItem.DrawRectangle.Top+item.ParentItem.DrawRectangle.Height/2),
                    //new PointF(item.ParentItem.DrawRectangle.Right+12,item.DrawRectangle.Top+item.DrawRectangle.Height/2),                    
                    new PointF(item.DrawRectangle.Left-12,item.DrawRectangle.Top+item.DrawRectangle.Height/2),                 
                    new PointF(item.DrawRectangle.Left,item.DrawRectangle.Top+item.DrawRectangle.Height/2),
                });
            }
            //展开折叠按钮
            if (item.Childrens != null && item.Childrens.Length > 0)
            {
                RectangleF _rect = new RectangleF(item.DrawRectangle.Right + 1, item.DrawRectangle.Top + (item.DrawRectangle.Height - 10) / 2, 10, 10);
                item.ExpansionRectangle = _rect;
                g.FillEllipse(new SolidBrush(this.BackColor), _rect);
                g.DrawEllipse(new Pen(new SolidBrush(Color.Black)), _rect);
                g.DrawLine(new Pen(new SolidBrush(lineColor)), _rect.Left + 2, _rect.Y + _rect.Height / 2, _rect.Right - 2, _rect.Y + _rect.Height / 2);
                if (!item.IsExpansion)
                {
                    g.DrawLine(new Pen(new SolidBrush(lineColor)), _rect.Left + _rect.Width / 2, _rect.Top + 2, _rect.Left + _rect.Width / 2, _rect.Bottom - 2);
                }
            }
        }

控件的单击和双击时间来处理展开折叠事件

 /// <summary>
        /// 双击处理，主要用于检测节点双击展开折叠
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="EventArgs"/> instance containing the event data.</param>
        void UCMindMapping_DoubleClick(object sender, EventArgs e)
        {
            var mouseLocation = this.PointToClient(Control.MousePosition);

            bool bln = CheckExpansionDoubleClick(dataSource, mouseLocation);
            if (bln)
            {
                ResetSize();
                this.Parent.Refresh();
            }
        }

        /// <summary>
        /// 单击处理，主要用于单击节点事件和，展开关闭圆圈处理
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="EventArgs"/> instance containing the event data.</param>
        void UCMindMapping_Click(object sender, EventArgs e)
        {
            var mouseLocation = this.PointToClient(Control.MousePosition);

            bool bln = CheckExpansionClick(dataSource, mouseLocation);
            if (bln)
            {
                ResetSize();
                this.Parent.Refresh();
            }
        }

  /// <summary>
        /// 双击检查
        /// </summary>
        /// <param name="item">The item.</param>
        /// <param name="mouseLocation">The mouse location.</param>
        /// <returns><c>true</c> if XXXX, <c>false</c> otherwise.</returns>
        private bool CheckExpansionDoubleClick(MindMappingItemEntity item, Point mouseLocation)
        {
            if (item == null)
                return false;
            else
            {
                if (item.DrawRectangle.Contains(mouseLocation))
                {
                    item.IsExpansion = !item.IsExpansion;
                    return true;
                }
                if (item.Childrens != null && item.Childrens.Length > 0)
                {
                    foreach (var child in item.Childrens)
                    {
                        var bln = CheckExpansionDoubleClick(child, mouseLocation);
                        if (bln)
                            return bln;
                    }
                }
            }
            return false;
        }

        /// <summary>
        /// 单击检查
        /// </summary>
        /// <param name="item">The item.</param>
        /// <param name="mouseLocation">The mouse location.</param>
        /// <returns><c>true</c> if XXXX, <c>false</c> otherwise.</returns>
        private bool CheckExpansionClick(MindMappingItemEntity item, Point mouseLocation)
        {
            if (item == null)
                return false;
            else
            {
                if (ItemClicked != null && item.WorkingRectangle.Contains(mouseLocation))
                {
                    ItemClicked(item, null);
                }
                else if (item.ExpansionRectangle.Contains(mouseLocation))
                {
                    item.IsExpansion = !item.IsExpansion;
                    return true;
                }
                if (item.Childrens != null && item.Childrens.Length > 0)
                {
                    foreach (var child in item.Childrens)
                    {
                        var bln = CheckExpansionClick(child, mouseLocation);
                        if (bln)
                            return bln;
                    }
                }
            }
            return false;
        }

完整代码

// ***********************************************************************
// Assembly         : HZH_Controls
// Created          : 2019-09-11
//
// ***********************************************************************
// <copyright file="UCMindMapping.cs">
//     Copyright by Huang Zhenghui(黄正辉) All, QQ group:568015492 QQ:623128629 Email:623128629@qq.com
// </copyright>
//
// Blog: https://www.cnblogs.com/bfyx
// GitHub：https://github.com/kwwwvagaa/NetWinformControl
// gitee：https://gitee.com/kwwwvagaa/net_winform_custom_control.git
//
// If you use this code, please keep this note.
// ***********************************************************************
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.ComponentModel;

namespace HZH_Controls.Controls
{
    /// <summary>
    /// Class UCMindMapping.
    /// Implements the <see cref="System.Windows.Forms.UserControl" />
    /// </summary>
    /// <seealso cref="System.Windows.Forms.UserControl" />
    internal class UCMindMapping : UserControl
    {
        /// <summary>
        /// The line color
        /// </summary>
        private Color lineColor = Color.Black;

        /// <summary>
        /// Gets or sets the color of the line.
        /// </summary>
        /// <value>The color of the line.</value>
        [Description("线条颜色"), Category("自定义")]
        public Color LineColor
        {
            get { return lineColor; }
            set
            {
                lineColor = value;
                Refresh();
            }
        }
        /// <summary>
        /// The split width
        /// </summary>
        private int splitWidth = 50;
        // private int itemHeight = 20;
        /// <summary>
        /// The padding
        /// </summary>
        private int padding = 20;

        /// <summary>
        /// The m rect working
        /// </summary>
        Rectangle m_rectWorking = Rectangle.Empty;
        /// <summary>
        /// Occurs when [item clicked].
        /// </summary>
        public event EventHandler ItemClicked;
        /// <summary>
        /// The data source
        /// </summary>
        private MindMappingItemEntity dataSource;
        /// <summary>
        /// Gets or sets the data source.
        /// </summary>
        /// <value>The data source.</value>
        [Description("数据源"), Category("自定义")]
        public MindMappingItemEntity DataSource
        {
            get { return dataSource; }
            set
            {
                dataSource = value;

                ResetSize();
            }
        }
        /// <summary>
        /// Initializes a new instance of the <see cref="UCMindMapping"/> class.
        /// </summary>
        public UCMindMapping()
        {
            this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
            this.SetStyle(ControlStyles.DoubleBuffer, true);
            this.SetStyle(ControlStyles.ResizeRedraw, true);
            this.SetStyle(ControlStyles.Selectable, true);
            this.SetStyle(ControlStyles.SupportsTransparentBackColor, true);
            this.SetStyle(ControlStyles.UserPaint, true);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.None;
            this.Click += UCMindMapping_Click;
            this.DoubleClick += UCMindMapping_DoubleClick;
            this.Load += UCMindMapping_Load;
        }

        /// <summary>
        /// Handles the Load event of the UCMindMapping control.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="EventArgs"/> instance containing the event data.</param>
        void UCMindMapping_Load(object sender, EventArgs e)
        {
            if (this.Parent != null)
            {
                //父控件大小改变时重置大小和位置
                this.Parent.SizeChanged += (a, b) =>
                {
                    ResetSize();
                };
            }
        }

        /// <summary>
        /// 双击处理，主要用于检测节点双击展开折叠
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="EventArgs"/> instance containing the event data.</param>
        void UCMindMapping_DoubleClick(object sender, EventArgs e)
        {
            var mouseLocation = this.PointToClient(Control.MousePosition);

            bool bln = CheckExpansionDoubleClick(dataSource, mouseLocation);
            if (bln)
            {
                ResetSize();
                this.Parent.Refresh();
            }
        }

        /// <summary>
        /// 单击处理，主要用于单击节点事件和，展开关闭圆圈处理
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="EventArgs"/> instance containing the event data.</param>
        void UCMindMapping_Click(object sender, EventArgs e)
        {
            var mouseLocation = this.PointToClient(Control.MousePosition);

            bool bln = CheckExpansionClick(dataSource, mouseLocation);
            if (bln)
            {
                ResetSize();
                this.Parent.Refresh();
            }
        }

        /// <summary>
        /// 双击检查
        /// </summary>
        /// <param name="item">The item.</param>
        /// <param name="mouseLocation">The mouse location.</param>
        /// <returns><c>true</c> if XXXX, <c>false</c> otherwise.</returns>
        private bool CheckExpansionDoubleClick(MindMappingItemEntity item, Point mouseLocation)
        {
            if (item == null)
                return false;
            else
            {
                if (item.DrawRectangle.Contains(mouseLocation))
                {
                    item.IsExpansion = !item.IsExpansion;
                    return true;
                }
                if (item.Childrens != null && item.Childrens.Length > 0)
                {
                    foreach (var child in item.Childrens)
                    {
                        var bln = CheckExpansionDoubleClick(child, mouseLocation);
                        if (bln)
                            return bln;
                    }
                }
            }
            return false;
        }

        /// <summary>
        /// 单击检查
        /// </summary>
        /// <param name="item">The item.</param>
        /// <param name="mouseLocation">The mouse location.</param>
        /// <returns><c>true</c> if XXXX, <c>false</c> otherwise.</returns>
        private bool CheckExpansionClick(MindMappingItemEntity item, Point mouseLocation)
        {
            if (item == null)
                return false;
            else
            {
                if (ItemClicked != null && item.WorkingRectangle.Contains(mouseLocation))
                {
                    ItemClicked(item, null);
                }
                else if (item.ExpansionRectangle.Contains(mouseLocation))
                {
                    item.IsExpansion = !item.IsExpansion;
                    return true;
                }
                if (item.Childrens != null && item.Childrens.Length > 0)
                {
                    foreach (var child in item.Childrens)
                    {
                        var bln = CheckExpansionClick(child, mouseLocation);
                        if (bln)
                            return bln;
                    }
                }
            }
            return false;
        }

        /// <summary>
        /// 引发 <see cref="E:System.Windows.Forms.Control.Paint" /> 事件。
        /// </summary>
        /// <param name="e">包含事件数据的 <see cref="T:System.Windows.Forms.PaintEventArgs" />。</param>
        protected override void OnPaint(PaintEventArgs e)
        {
            try
            {
                base.OnPaint(e);
                if (m_rectWorking == Rectangle.Empty || m_rectWorking == null)
                    return;
                var g = e.Graphics;
                g.SetGDIHigh();

                int intHeight = dataSource.AllChildrensMaxShowHeight;
                dataSource.WorkingRectangle = new RectangleF(m_rectWorking.Left, m_rectWorking.Top + (m_rectWorking.Height - intHeight) / 2, m_rectWorking.Width, intHeight);

                DrawItem(dataSource, g);
            }
            catch (Exception exc)
            {
                MessageBox.Show(exc.ToString(), "错误");
            }
        }

        /// <summary>
        /// 画节点
        /// </summary>
        /// <param name="item">The item.</param>
        /// <param name="g">The g.</param>
        private void DrawItem(MindMappingItemEntity item, Graphics g)
        {
            //节点
            var size = g.MeasureString(item.Text, item.Font);
            item.DrawRectangle = new RectangleF(item.WorkingRectangle.Left + 2, item.WorkingRectangle.Top + (item.WorkingRectangle.Height - size.Height) / 2 + 2, size.Width + 4, size.Height + 4);
            GraphicsPath drawPath = item.DrawRectangle.CreateRoundedRectanglePath(5);
            g.FillPath(new SolidBrush(item.BackColor), drawPath);
            g.DrawString(item.Text, item.Font, new SolidBrush(item.ForeColor), item.DrawRectangle.Location.X + 2, item.DrawRectangle.Location.Y + 2);
            //子节点
            if (item.Childrens != null && item.IsExpansion)
            {
                for (int i = 0; i < item.Childrens.Length; i++)
                {
                    var child = item.Childrens[i];
                    if (i == 0)
                    {
                        child.WorkingRectangle = new RectangleF(item.DrawRectangle.Right + splitWidth, item.WorkingRectangle.Top, item.WorkingRectangle.Width - (item.DrawRectangle.Width + splitWidth), child.AllChildrensMaxShowHeight);
                    }
                    else
                    {
                        child.WorkingRectangle = new RectangleF(item.DrawRectangle.Right + splitWidth, item.Childrens[i - 1].WorkingRectangle.Bottom, item.WorkingRectangle.Width - (item.DrawRectangle.Width + splitWidth), child.AllChildrensMaxShowHeight);
                    }
                    DrawItem(child, g);
                }
            }
            //连线
            if (item.ParentItem != null)
            {
                g.DrawLines(new Pen(new SolidBrush(lineColor), 1), new PointF[] 
                { 
                    new PointF(item.ParentItem.DrawRectangle.Right,item.ParentItem.DrawRectangle.Top+item.ParentItem.DrawRectangle.Height/2),
                    new PointF(item.ParentItem.DrawRectangle.Right+12,item.ParentItem.DrawRectangle.Top+item.ParentItem.DrawRectangle.Height/2),
                    //new PointF(item.ParentItem.DrawRectangle.Right+12,item.DrawRectangle.Top+item.DrawRectangle.Height/2),                    
                    new PointF(item.DrawRectangle.Left-12,item.DrawRectangle.Top+item.DrawRectangle.Height/2),                 
                    new PointF(item.DrawRectangle.Left,item.DrawRectangle.Top+item.DrawRectangle.Height/2),
                });
            }
            //展开折叠按钮
            if (item.Childrens != null && item.Childrens.Length > 0)
            {
                RectangleF _rect = new RectangleF(item.DrawRectangle.Right + 1, item.DrawRectangle.Top + (item.DrawRectangle.Height - 10) / 2, 10, 10);
                item.ExpansionRectangle = _rect;
                g.FillEllipse(new SolidBrush(this.BackColor), _rect);
                g.DrawEllipse(new Pen(new SolidBrush(Color.Black)), _rect);
                g.DrawLine(new Pen(new SolidBrush(lineColor)), _rect.Left + 2, _rect.Y + _rect.Height / 2, _rect.Right - 2, _rect.Y + _rect.Height / 2);
                if (!item.IsExpansion)
                {
                    g.DrawLine(new Pen(new SolidBrush(lineColor)), _rect.Left + _rect.Width / 2, _rect.Top + 2, _rect.Left + _rect.Width / 2, _rect.Bottom - 2);
                }
            }
        }


        /// <summary>
        /// 重置大小
        /// </summary>
        private void ResetSize()
        {
            if (this.Parent == null)
                return;
            try
            {
                ControlHelper.FreezeControl(this, true);
                if (dataSource == null)
                {
                    m_rectWorking = Rectangle.Empty;
                    this.Size = this.Parent.Size;
                }
                else
                {
                    int intWidth = dataSource.AllChildrensMaxShowWidth;
                    int intHeight = dataSource.AllChildrensMaxShowHeight;
                    this.Width = intWidth + padding * 2;
                    this.Height = intHeight + padding * 2;
                    if (this.Width < this.Parent.Width)
                        this.Width = this.Parent.Width;
                    m_rectWorking = new Rectangle(padding, padding, intWidth, intHeight);
                    if (this.Height > this.Parent.Height)
                    {
                        //this.Location = new Point(0, 0);
                    }
                    else
                        this.Location = new Point(0, (this.Parent.Height - this.Height) / 2);
                }
            }
            finally
            {
                ControlHelper.FreezeControl(this, false);
            }
        }
    }
}

最后再添加一个父控件，来包裹该控件，用以可以有滚动条的处理

添加一个用户控件UCMindMappingPanel，控件上添加一个上面新增的ucMindMapping，

完整代码

// ***********************************************************************
// Assembly         : HZH_Controls
// Created          : 2019-09-11
//
// ***********************************************************************
// <copyright file="UCMindMappingPanel.cs">
//     Copyright by Huang Zhenghui(黄正辉) All, QQ group:568015492 QQ:623128629 Email:623128629@qq.com
// </copyright>
//
// Blog: https://www.cnblogs.com/bfyx
// GitHub：https://github.com/kwwwvagaa/NetWinformControl
// gitee：https://gitee.com/kwwwvagaa/net_winform_custom_control.git
//
// If you use this code, please keep this note.
// ***********************************************************************
using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace HZH_Controls.Controls
{
    /// <summary>
    /// Class UCMindMappingPanel.
    /// Implements the <see cref="System.Windows.Forms.UserControl" />
    /// </summary>
    /// <seealso cref="System.Windows.Forms.UserControl" />
    public partial class UCMindMappingPanel : UserControl
    {
        /// <summary>
        /// The data source
        /// </summary>
        private MindMappingItemEntity dataSource;

        /// <summary>
        /// Gets or sets the data source.
        /// </summary>
        /// <value>The data source.</value>
        [Description("数据源"), Category("自定义")]
        public MindMappingItemEntity DataSource
        {
            get { return dataSource; }
            set
            {
                dataSource = value;
                this.ucMindMapping1.DataSource = value;
            }
        }
        /// <summary>
        /// Gets or sets the data source.
        /// </summary>
        /// <value>The data source.</value>
        [Description("数据源"), Category("自定义")]
        public event EventHandler ItemClicked;

        /// <summary>
        /// The line color
        /// </summary>
        private Color lineColor = Color.Black;

        /// <summary>
        /// Gets or sets the color of the line.
        /// </summary>
        /// <value>The color of the line.</value>
        [Description("线条颜色"), Category("自定义")]
        public Color LineColor
        {
            get { return lineColor; }
            set
            {
                lineColor = value;
                this.ucMindMapping1.LineColor = value;
            }
        }
        /// <summary>
        /// Initializes a new instance of the <see cref="UCMindMappingPanel"/> class.
        /// </summary>
        public UCMindMappingPanel()
        {
            this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
            this.SetStyle(ControlStyles.DoubleBuffer, true);
            this.SetStyle(ControlStyles.ResizeRedraw, true);
            this.SetStyle(ControlStyles.Selectable, true);
            this.SetStyle(ControlStyles.SupportsTransparentBackColor, true);
            this.SetStyle(ControlStyles.UserPaint, true);
            InitializeComponent();
            ucMindMapping1.ItemClicked += ucMindMapping1_ItemClicked;
        }

        void ucMindMapping1_ItemClicked(object sender, EventArgs e)
        {
            if (ItemClicked != null)
            {
                ItemClicked(sender, e);
            }
        }
    }
}

namespace HZH_Controls.Controls
{
    partial class UCMindMappingPanel
    {
        /// <summary> 
        /// 必需的设计器变量。
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary> 
        /// 清理所有正在使用的资源。
        /// </summary>
        /// <param name="disposing">如果应释放托管资源，为 true；否则为 false。</param>
        protected override void Dispose(bool disposing)
        {
            if (disposing && (components != null))
            {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region 组件设计器生成的代码

        /// <summary> 
        /// 设计器支持所需的方法 - 不要
        /// 使用代码编辑器修改此方法的内容。
        /// </summary>
        private void InitializeComponent()
        {
            this.ucMindMapping1 = new HZH_Controls.Controls.UCMindMapping();
            this.SuspendLayout();
            // 
            // ucMindMapping1
            // 
            this.ucMindMapping1.Location = new System.Drawing.Point(0, 0);
            this.ucMindMapping1.Name = "ucMindMapping1";
            this.ucMindMapping1.Size = new System.Drawing.Size(200, 200);
            this.ucMindMapping1.TabIndex = 0;
            // 
            // UCMindMappingPanel
            // 
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.None;
            this.AutoScroll = true;
            this.BackColor = System.Drawing.Color.White;
            this.Controls.Add(this.ucMindMapping1);
            this.Name = "UCMindMappingPanel";
            this.Size = new System.Drawing.Size(200, 200);
            this.ResumeLayout(false);

        }

        #endregion

        private UCMindMapping ucMindMapping1;
    }
}

最后的话

如果你喜欢的话，请到 https://gitee.com/kwwwvagaa/net_winform_custom_control 点个星星吧