C#使用Stateless和箭头控件实现状态机的控制及显示

之前开发一个小工具，内部实现一个状态机，并显示状态机当前状态及状态间的转移过程。我使用了Stateless开源类库及一个开源自定义箭头控件。自定义箭头控件是HZHControls其中一个控件，我单独把它从源码中独立出来。主要对代码做了以下改动：

• 添加、删除、替换了一部分注释。
• 更改了一些内部事件触发逻辑，时间长了忘了具体改了什么，但不会影响主体功能。
• 在 protected override void OnPaint(PaintEventArgs e) 中内联了外部依赖的 public static void SetGDIHigh(Graphics g) 函数，我在原作者博客的评论下有说明。

以上涉及到的相关项目的链接如下

• Stateless开源类库：https://github.com/dotnet-state-machine/stateless
• HZHControls控件库：https://gitee.com/kwwwvagaa/net_winform_custom_control
• Stateless使用方法：.NET中的状态机库Stateless
• 自定义箭头控件介绍：（六十三）c#Winform自定义控件-箭头（工业）-HZHControls

自定义箭头控件的代码很有学习价值，可以在其基础上扩展出其它形状的控件。使用时新建一个用户控件然后复制代码即可，代码如下：

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 ExtControls
{    
    public partial class  Arrow : UserControl
    {
        private Color arrowColor = Color.DarkGray;
        /// <summary>
        /// 获取设置箭头颜色
        /// </summary>
        [Description("箭头颜色"), Category("自定义")]
        public Color ArrowColor
        {
            get { return arrowColor; }
            set
            {
                arrowColor = value;
                Refresh();
            }
        }
        
        private Color? borderColor = null;
        /// <summary>
        /// 获取或设置箭头边框颜色
        /// </summary>
        [Description("箭头边框颜色，为空则无边框"), Category("自定义")]
        public Color? BorderColor
        {
            get { return borderColor; }
            set
            {
                borderColor = value;
                Refresh();
            }
        }
        
        /// <summary>
        /// 箭头方向
        /// </summary>
        private ArrowDirection direction = ArrowDirection.Right;

        /// <summary>
        /// 获取或设置箭头方向
        /// </summary>
        /// <value>The direction.</value>
        [Description("获取或设置箭头方向"), Category("自定义")]
        public ArrowDirection Direction
        {
            get { return direction; }
            set
            {
                direction = value;
                ResetMyPath();
                Refresh();
            }
        }

        private string text;
        /// <summary>
        /// 与控件关联的文本。
        /// </summary>
        [Bindable(true)]
        [Browsable(true)]
        [DesignerSerializationVisibility(DesignerSerializationVisibility.Visible)]
        [EditorBrowsable(EditorBrowsableState.Always)]
        [Localizable(true)]
        [Description("与控件关联的文本"), Category("自定义")]
        public override string Text
        {
            get
            {
                return text;
            }
            set
            {
                text = value;
                Refresh();
            }
        }
        /// <summary>
        /// 图形空间
        /// </summary>
        GraphicsPath myPath;
        /// <summary>
        /// 初始化UCArrow类的新实例。
        /// </summary>
        public Arrow()
        {
            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.ForeColor = Color.White;
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.None;
            this.SizeChanged += UCArrow_NeedResetChanged;
            this.Size = new Size(100, 50);
            this.ForeColorChanged += UCArrow_NeedResetChanged;
            this.ForeColor = Color.Black;
            this.FontChanged += UCArrow_NeedResetChanged;
        }

        /// <summary>
        /// 需要重绘控件的事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void UCArrow_NeedResetChanged(object sender, EventArgs e)
        {
            ResetMyPath();
        }

        /// <summary>
        /// 重置图形
        /// </summary>
        private void ResetMyPath()
        {
            Point[] ps = null;
            switch (direction)
            {
                case ArrowDirection.Left:
                    ps = new Point[] 
                    { 
                        new Point(0,this.Height/2),
                        new Point(40,0),
                        new Point(40,this.Height/4),
                        new Point(this.Width-1,this.Height/4),
                        new Point(this.Width-1,this.Height-this.Height/4),
                        new Point(40,this.Height-this.Height/4),
                        new Point(40,this.Height),
                        new Point(0,this.Height/2)
                    };
                    break;
                case ArrowDirection.Right:
                    ps = new Point[] 
                    {
                        new Point(0,this.Height/4),
                        new Point(this.Width-40,this.Height/4),
                        new Point(this.Width-40,0),
                        new Point(this.Width-1,this.Height/2),
                        new Point(this.Width-40,this.Height),
                        new Point(this.Width-40,this.Height-this.Height/4),                      
                        new Point(0,this.Height-this.Height/4),
                        new Point(0,this.Height/4)
                    };
                    break;
                case ArrowDirection.Top:
                    ps = new Point[] 
                    {
                       new Point(this.Width/2,0),
                       new Point(this.Width,40),
                       new Point(this.Width-this.Width/4,40),
                       new Point(this.Width-this.Width/4,this.Height-1),
                       new Point(this.Width/4,this.Height-1),
                       new Point(this.Width/4,40),
                       new Point(0,40),
                       new Point(this.Width/2,0),
                    };
                    break;
                case ArrowDirection.Bottom:
                    ps = new Point[] 
                    {
                       new Point(this.Width-this.Width/4,0),
                       new Point(this.Width-this.Width/4,this.Height-40),
                       new Point(this.Width,this.Height-40),
                       new Point(this.Width/2,this.Height-1),
                       new Point(0,this.Height-40),
                       new Point(this.Width/4,this.Height-40),
                       new Point(this.Width/4,0),
                       new Point(this.Width-this.Width/4,0),                      
                    };
                    break;
                case ArrowDirection.Left_Right:
                    ps = new Point[] 
                    { 
                        new Point(0,this.Height/2),
                        new Point(40,0),
                        new Point(40,this.Height/4),
                        new Point(this.Width-40,this.Height/4),
                        new Point(this.Width-40,0),
                        new Point(this.Width-1,this.Height/2),
                        new Point(this.Width-40,this.Height),
                        new Point(this.Width-40,this.Height-this.Height/4),
                        new Point(40,this.Height-this.Height/4),
                        new Point(40,this.Height),
                        new Point(0,this.Height/2),                       
                    };
                    break;
                case ArrowDirection.Top_Bottom:
                    ps = new Point[] 
                    {
                       new Point(this.Width/2,0),
                       new Point(this.Width,40),
                       new Point(this.Width-this.Width/4,40),
                       new Point(this.Width-this.Width/4,this.Height-40),
                       new Point(this.Width,this.Height-40),
                       new Point(this.Width/2,this.Height-1),
                       new Point(0,this.Height-40),
                       new Point(this.Width/4,this.Height-40),
                       new Point(this.Width/4,40),
                       new Point(0,40),
                       new Point(this.Width/2,0),                      
                    };
                    break;
            }
            myPath = new GraphicsPath();
            myPath.AddLines(ps);
            myPath.CloseAllFigures();
        }

        /// <summary>
        /// 引发Control.Paint 事件。
        /// </summary>
        /// <param name="e"></param>
        protected override void OnPaint(PaintEventArgs e)
        {
            base.OnPaint(e);
            var g = e.Graphics;

            // 设置GDI高质量模式抗锯齿
            g.SmoothingMode = SmoothingMode.AntiAlias;
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.CompositingQuality = CompositingQuality.HighQuality;

            g.FillPath(new SolidBrush(arrowColor), myPath);

            if (borderColor != null && borderColor != Color.Empty)
                g.DrawPath(new Pen(new SolidBrush(borderColor.Value)), myPath);
            if (!string.IsNullOrEmpty(text))
            {
                var size = g.MeasureString(Text, Font);
                g.DrawString(Text, Font, new SolidBrush(ForeColor), new PointF((this.Width - size.Width) / 2, (this.Height - size.Height) / 2));
            }
        }

        
    }

    /// <summary>
    /// 箭头方向的描述枚举
    /// </summary>
    public enum ArrowDirection
    {
        /// <summary>
        /// 向左
        /// </summary>
        Left,
        /// <summary>
        /// 向右
        /// </summary>
        Right,
        /// <summary>
        /// 向上
        /// </summary>
        Top,
        /// <summary>
        /// 向下
        /// </summary>
        Bottom,
        /// <summary>
        /// 向左向右
        /// </summary>
        Left_Right,
        /// <summary>
        /// 向上向下
        /// </summary>
        Top_Bottom
    }
}