C#用户控件之温度计设计

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

namespace DemoThermometer
{
  public partial class Thermometer : UserControl
  {
    #region 属性与构造函数

    private int interval = 10;

    /// <summary>
    /// 刻度间隔
    /// </summary>
    public int Interval
    {
      get { return interval; }

      set { interval = value; }
    }

    private int minValue = -50;

    /// <summary>
    /// 最低温度
    /// </summary>
    public int MinValue
    {
      get { return minValue; }

      set { minValue = value; }
    }

    private int maxValue = 50;

    /// <summary>
    /// 最高温度
    /// </summary>
    public int MaxValue
    {
      get { return maxValue; }

      set { maxValue = value; }
    }

    private float curValue = 0;

    /// <summary>
    /// 当前温度
    /// </summary>
    public float CurValue
    {
      get { return curValue; }

      set { curValue = value; }
    }

    private Color thermoColor = Color.Red;

    /// <summary>
    /// 温度条颜色
    /// </summary>
    public Color ThermoColor
    {
      get { return thermoColor; }

      set { thermoColor = value; }
    }

    private Color backGroundColor = Color.SkyBlue;

    /// <summary>
    /// 温度计背景色
    /// </summary>
    public Color BackGroundColor
    {
      get { return backGroundColor; }

      set { backGroundColor = value; }
    }

    private Font thermoFont=new Font("宋体",10,FontStyle.Regular);

    /// <summary>
    /// 温度计上字体
    /// </summary>
    public Font ThermoFont
    {
      get { return thermoFont; }

      set { thermoFont = value; }
    }

    private string thermoTitle = "温度计";

    /// <summary>
    /// 标题
    /// </summary>
    public string ThermoTitle
    {
      get { return this.thermoTitle; }
      set { this.thermoTitle = value; }
    }

    private bool showTip = false;

    /// <summary>
    /// 是否显示提示
    /// </summary>
    public bool ShowTip
    {
      get { return showTip; }

      set { showTip = value; }
    }

    private ToolTip tip=new ToolTip();

    public Thermometer()
    {
      InitializeComponent();
    }

    #endregion

    protected override void OnPaint(PaintEventArgs e)
    {
      
      //base.OnPaint(e);
      //this.BackColor = this.backGroundColor;
      int width = this.Width;
      int height = this.Height - 50 ;
      Graphics g = e.Graphics;
      int c_x = width / 2;
      int c_y = height / 2;
      int padding = this.Padding.All;//空白
      int r = (width - 2 * padding)/2;//半径
      int d = 2 * r;//直径
      int dis = 2;//两个半圆之间的间隔
      int dis2 = 2 * dis;//填充与边框之间的距离
      int startAngle1 = -180;
      int startAngle2 = 0;
      int sweepAngle1 = 180;
      //首先画顶端一个半圆
      g.DrawPie(Pens.Black, new Rectangle(padding, padding, d, d),startAngle1, sweepAngle1);
      g.DrawPie(Pens.Black, new Rectangle(padding+ dis, padding+ dis, d-2* dis, d-2* dis), startAngle1, sweepAngle1);
      //填充背景色
      g.FillPie(new SolidBrush(this.backGroundColor), new Rectangle(padding + dis2, padding + dis2, d - 2*dis2, d - 2*dis2), startAngle1, sweepAngle1);
      //画底端一个半圆
      g.DrawPie(Pens.Black, new Rectangle(padding, height-d-padding, d, d), startAngle2, sweepAngle1);
      g.DrawPie(Pens.Black, new Rectangle(padding + dis, height-d-padding + dis, d - 2*dis, d - 2*dis), startAngle2, sweepAngle1);
      g.FillPie(new SolidBrush(this.backGroundColor), new Rectangle(padding + dis2, height - d - padding+dis2, d - 2*dis2, d - 2*dis2), startAngle2, sweepAngle1);
      //画一个矩形
      g.DrawRectangle(Pens.Black, new Rectangle(padding, padding + r, d, height - d - 2 * padding));
      g.DrawRectangle(Pens.Black, new Rectangle(padding+dis, padding + r+dis, d-2*dis, height - d - 2 * padding-2*dis));
      //背景色填充，去掉边界线
      g.FillRectangle(new SolidBrush(this.backGroundColor), new Rectangle(padding+3, padding + r-2, 2 * r-6, 6));
      g.FillRectangle(new SolidBrush(this.backGroundColor), new Rectangle(padding + 3, height-r-padding-4, 2 * r - 6, 8));
      //背景色填充中间部分
      g.FillRectangle(new SolidBrush(this.backGroundColor), new Rectangle(padding + dis2, padding + r + dis2, d - 2*dis2, height -d - 2 * padding - 2*dis2));
      //画刻度
      int s_s_x_1 = padding + r - 20;
      int s_s_x_2 = width-padding - r + 20;
      int s_s_y = padding + r+4;
      int total = this.maxValue - this.minValue;
      int scale_width = 5;//刻度宽度
      int scale = total / this.interval;
      int pscale = (height - 2 * r - 2 * padding) / this.interval;//像素间隔
                                    
      //竖线
      g.DrawLine(Pens.Black, new Point(s_s_x_1, s_s_y ), new Point(s_s_x_1, s_s_y + this.interval* pscale));
      g.DrawLine(Pens.Black, new Point(s_s_x_2, s_s_y), new Point(s_s_x_2, s_s_y + this.interval * pscale));
      for (int i = 0; i <= this.interval; i++) {
        //横线刻度
        g.DrawLine(Pens.Black, new Point(s_s_x_1- scale_width, s_s_y + i * pscale), new Point(s_s_x_1, s_s_y + i * pscale));
        g.DrawLine(Pens.Black, new Point(s_s_x_2, s_s_y + i * pscale), new Point(s_s_x_2 + scale_width, s_s_y + i * pscale));
        //画刻度数字

        g.DrawString((this.maxValue - (scale * i)).ToString(), this.thermoFont, new SolidBrush( this.ForeColor), new Point(s_s_x_1-35, s_s_y + i * pscale-10));
        g.DrawString((this.maxValue - (scale * i)).ToString(), this.thermoFont, new SolidBrush(this.ForeColor), new Point(s_s_x_2 + 10, s_s_y + i * pscale-10));
      }
      int white_width = 3;//中间白色线宽度
      //画条白色细线
      g.FillRectangle(Brushes.White, new Rectangle(c_x- white_width, r/2, white_width*2, height-r));
      //在底部画一个圆球
      g.FillPie(new SolidBrush(this.thermoColor), new Rectangle(c_x-r/2+5, height - r - padding, r-10, r-10), 0, 360);
      //根据当前温度画红色线
      int red_width = 5;//红色温度线宽度
      float ii = ( this.curValue-this.minValue) / this.interval;
      g.FillRectangle(new SolidBrush(this.thermoColor), new RectangleF(c_x - red_width, height - r - padding- (ii * pscale)-4, 2* red_width, ii * pscale+5));//此处有一像素的误差
      //画标志字符单℃位
      g.DrawString("℃", this.thermoFont, new SolidBrush(this.ForeColor), new Point(c_x - 30, r / 2 - 10));
      Font titleFont = new Font("宋体", 13, FontStyle.Bold);
      //绘制标题
      SizeF tsize = g.MeasureString(this.thermoTitle, titleFont);
      g.DrawString(this.thermoTitle, titleFont, new SolidBrush(this.ForeColor), new PointF(c_x- (tsize.Width/2), height + 5));
      string cur = string.Format("当前温度：{0}℃", this.curValue);
      SizeF tsize2 = g.MeasureString(cur, this.thermoFont);
      g.DrawString(cur, this.thermoFont, new SolidBrush(this.thermoColor), new PointF(c_x - (tsize2.Width / 2), height + 10+tsize.Height));
    }

    /// <summary>
    /// 当鼠标覆盖进去时
    /// </summary>
    /// <param name="e"></param>
    protected override void OnMouseHover(EventArgs e)
    {
      this.showTip = true;
      //需要显示的内容
      int x = this.Width / 2;
      int y = (this.Height-50) / 2;
      StringBuilder sbTips = new StringBuilder();
      //sbTips.AppendLine(this.ThermoTitle);
      sbTips.AppendLine(string.Format("当前温度：{0}", this.curValue));
      sbTips.AppendLine("单位：℃");
      tip.ToolTipTitle = this.ThermoTitle;
      tip.IsBalloon = true;
      tip.UseFading = true;
      //t.SetToolTip(this, sbTips.ToString());
      tip.Show(sbTips.ToString(), this, x, y);
    }
    

    protected override void OnMouseLeave(EventArgs e)
    {
      this.showTip = false;
      tip.Hide(this);
    }
  }
}