C#自定义控件 ————进度条

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;
using System.Threading;

namespace WindowsFormsApplication19
{
    public partial class CustomControl1 : Control
    {
        Bitmap background;
        //进度条的最大值，最小值，和当前值
        private float min_value = 0f;
        private float max_value = 100f;
        private float current_value = 0;
        private int min_value_protect_value = 0;//用户保护max和min变量只赋值一次的值
        private int max_value_protect_value = 0;//

        //控件的最小吃寸
        private int min_size;
        //三个颜色，最外层，中间层和最内填充层
        private Color edge_line_color = Color.FromArgb(150, 174, 193);
        private Color edge_2_line_color = Color.FromArgb(93, 136, 163);
        private Color inside_fill_color = Color.FromArgb(231, 230, 235);
        //字体颜色
        private Color str_color = Color.Black;
        //最外层和中间层的宽度
        private float edge_line_width = 5f;
        private float edge_2_line_width = 5f;

        //事件
        public delegate void vaule_change_invoke(EventArgs args);
        public event vaule_change_invoke value_change;//值改变时触发的事件
        public event vaule_change_invoke progress_finshed;//进度条跑完时触发的事件

        //这里我暂时不对外开放接口，控件样式固定api用户可以设置
        /*
        public Color Edge_line_color
        {
            get { return edge_line_color; }
            set { edge_line_color = value; }
        }

        public Color Edge_2_line_color
        {
            get { return edge_2_line_color; }
            set { edge_2_line_color = value; }
        }

        public Color Inside_fill_color
        {
            get { return inside_fill_color; }
            set { inside_fill_color = value; }
        }

        public Color Str_color
        {
            get { return str_color; }
            set { str_color = value; }
        }

        public float Edge_line_width
        {
            get { return edge_line_width; }
            set
            {
                if (value > 0)
                    edge_line_width = value;
            }
        }

        public float Edge_2_line_width
        {
            get { return edge_2_line_width; }
            set
            {
                if (value > 0)
                    edge_2_line_width = value;
            }
        }
        */


        public float Min_value
        {
            get { return min_value; }
            set
            {
                if (value >= 0&&value<max_value && min_value_protect_value == 0)
                {
                    min_value = value;
                    current_value = value;
                    min_value_protect_value = 1;
                }
            }
        }

        public float Max_value
        {
            get { return max_value; }
            set
            {
                if (value > 0 && value > Min_value && max_value_protect_value == 0)
                {
                    max_value = value;
                    max_value_protect_value=1;
                }
            }
        }

        public float Current_value
        {
            get { return current_value; }
            set
            {
                if (value >= min_value && value <= max_value)
                {
                    current_value = value;
                    //触发派生重写方法
                    this.onvaluechange(new EventArgs());
                    //重绘控件
                    this.Invalidate();
                    if (progress_finshed != null)
                    {
                        //进度条跑完时触发
                        if (max_value == current_value)
                            this.progress_finshed(new EventArgs());

                    }
                    if (value_change != null)
                    {
                        //触发事件
                        this.value_change(new EventArgs());
                    }
                }
            }
        }

        public CustomControl1()
        {
            InitializeComponent();
            setinfo();
            //这里触发一次OnInvalidated，保证在onpaint前建立背景位图
            this.Invalidate();
            min_size = (int)(edge_2_line_width * 2 + edge_line_width * 2 + 50);
        }

        /// <summary>
        /// 绘图优化
        /// </summary>
        private void setinfo()
        {
            this.SetStyle(ControlStyles.OptimizedDoubleBuffer, true);
            this.SetStyle(ControlStyles.ResizeRedraw, true);
            this.SetStyle(ControlStyles.UserPaint, true);
            this.SetStyle(ControlStyles.AllPaintingInWmPaint, true);
        }

        /// <summary>
        /// 值修改触发的方法
        /// </summary>
        /// <param name="eventArgs"></param>
        protected virtual void onvaluechange(EventArgs eventArgs)
        {

        }

        protected override void OnResize(EventArgs e)
        {
            //保证控件最小尺寸
            int temp = Math.Min(Width, Height);
            temp = temp > min_size ? temp : min_size;
            Width = Height = temp;
            build_bitmap_buffer();
            this.Invalidate();
            base.OnResize(e);
        }

        /// <summary>
        /// 控件及子控件重绘
        /// </summary>
        /// <param name="pe"></param>
        protected override void OnPaint(PaintEventArgs pe)
        {
            base.OnPaint(pe);
        }

        /// <summary>
        /// 控件重绘
        /// </summary>
        /// <param name="e"></param>
        protected override void OnInvalidated(InvalidateEventArgs e)
        {
            
            if (background != null)
                update_the_progress_bar();
            else
            {
                build_bitmap_buffer();
            }
            base.OnInvalidated(e);
        }

        /// <summary>
        /// 创建背景缓冲位图
        /// </summary>
        private void build_bitmap_buffer()
        {
            if (background != null)
            {
                background.Dispose();
            }
            background = new Bitmap(Width, Width);
            Graphics g = Graphics.FromImage(background);
            g.Clear(Color.Transparent);
            g.Dispose();
        }

        /// <summary>
        /// 根据当前值更新进度条
        /// </summary>
        private void update_the_progress_bar()
        {
            Graphics g = Graphics.FromImage(background);
            Draw_with_HighQuality(g);
            g.Clear(Color.Transparent);
            Pen p = new Pen(edge_line_color, edge_line_width);
            #region 绘制最外部圆
            int x_y = (int)(edge_line_width / 2);
            int w_h = Width - (int)edge_line_width;
            Rectangle rect = new Rectangle(x_y, x_y, w_h, w_h);
            g.DrawEllipse(p, rect);
            #endregion

            #region 绘制第二层圆
            p.Width = edge_2_line_width;
            p.Color = edge_2_line_color;
            x_y += (int)(edge_line_width / 2 + edge_2_line_width / 2);
            w_h = Width - (int)(edge_line_width * 2 + edge_2_line_width);
            rect = new Rectangle(x_y, x_y, w_h, w_h);
            g.DrawEllipse(p, rect);
            #endregion
            p.Dispose();

            #region 绘制扇形
            Brush sb = new SolidBrush(inside_fill_color);
            x_y = (int)(edge_line_width + edge_2_line_width);
            w_h = Width - x_y * 2;
            rect = new Rectangle(x_y, x_y, w_h, w_h);
            float rad = (current_value - min_value) / (max_value - min_value);
            float frad = (360 * rad);
            g.FillPie(sb, rect, -90, frad);
            StringFormat sf = new StringFormat();
            sf.Alignment = StringAlignment.Center;
            sf.LineAlignment = StringAlignment.Center;
            g.DrawString((rad * 100).ToString() + "%", new Font("宋体", 12, FontStyle.Bold), new SolidBrush(str_color), this.ClientRectangle, sf);
            #endregion

            g.Dispose();
            this.BackgroundImage = background;
        }

        /// <summary>
        /// 高质量绘图
        /// </summary>
        /// <param name="g">绘图工具graphics</param>
        private void Draw_with_HighQuality(Graphics g)
        {
            g.SmoothingMode = SmoothingMode.AntiAlias;
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            g.CompositingQuality = CompositingQuality.HighQuality;
        }
    }
}