1using System;
  2using System.IO;
  3using System.Data;
  4using System.Drawing;
  5using System.Drawing.Text;
  6using System.Drawing.Drawing2D;
  7using System.Drawing.Imaging;
  8
  9using MyBookShop.DataAccessHelper;
 10//该源码下载自www.51aspx.com(５1ａｓｐｘ．ｃｏｍ)
 11
 12namespace MyBookShop.BusinessLogicLayer
 13...{
 14    /**//// <summary>
 15    /// 一个通用的画饼图的类
 16    /// </summary>
 17    public class Chart
 18    ...{
 19        private const int SIDE_LENGTH=400;
 20        private const int PIE_DIAMETER=200;
 21
 22        /**//// <summary>
 23        /// 画饼图方法
 24        /// </summary>
 25        /// <param name="title">饼图标题</param>
 26        /// <param name="subTitle">子标题</param>
 27        /// <param name="width">宽</param>
 28        /// <param name="height">高</param>
 29        /// <param name="dt">数据来源表</param>
 30        /// <param name="targetFile">生成的图形保存目标文件</param>
 31        /// <param name="descColumn">文字说明列</param>
 32        /// <param name="dataColumn">显示在统计图上的数据列名</param>
 33        public static void DrawPie(string title,string subTitle,int width,int height,DataTable dt,string targetFile,string descColumn,string dataColumn)
 34        ...{
 35            //创建一个位图对象
 36            Bitmap bm=new Bitmap(width,height);
 37            Graphics g=Graphics.FromImage(bm);
 38 
 39            //将图象"缩放"到指定面积
 40            g.ScaleTransform(Convert.ToSingle(width)/SIDE_LENGTH,Convert.ToSingle(height)/SIDE_LENGTH);
 41 
 42            //画饼图所在的线框
 43            g.Clear(Color.White);
 44            g.DrawRectangle(Pens.Black,0,0,SIDE_LENGTH-1,SIDE_LENGTH-1);
 45 
 46            //画标题title,副标题subTitle
 47            g.DrawString(title,new Font("宋体",14),Brushes.Black,new PointF(5,5)); 
 48            g.DrawString(subTitle,new Font("宋体",12),Brushes.Black,new PointF(7,35));
 49 
 50            //画饼图
 51            float curAngle=0;        //当前所画到的角度
 52            float totalAngle=0;        //总的角度
 53            float sumData=0;        //计算所要统计的数据之和
 54            
 55            //计算所要统计的数据之和
 56            foreach(DataRow dr in dt.Rows)
 57            ...{
 58                if(dr[dataColumn]!=DBNull.Value)
 59                    sumData+=Convert.ToSingle(dr[dataColumn]);
 60            }
 61
 62            //循环画出每一个扇形,以及其说明
 63            int colorIndex=0;        //颜色
 64            float percent=0;        //每一个种类的百分比
 65            g.DrawRectangle(Pens.Black,100,270,300,130);    //说明线框
 66            PointF boxOrigin=new PointF(110,275);            //说明标签起始位置
 67            PointF textOrigin=new PointF(135,275);            //说明文字起始位置
 68
 69            //循环画出每一个扇形
 70            foreach(DataRow row in dt.Rows)
 71            ...{
 72                if(row[dataColumn]!=System.DBNull.Value)
 73                ...{
 74                    colorIndex++;
 75
 76                    //扇形
 77                    curAngle=Convert.ToSingle(row[dataColumn])/sumData*360;
 78                    g.FillPie(new SolidBrush(GetColor(colorIndex)),100,60,PIE_DIAMETER,PIE_DIAMETER,totalAngle,curAngle);
 79                    g.DrawPie(Pens.Black,100,60,PIE_DIAMETER,PIE_DIAMETER,totalAngle,curAngle);
 80                    totalAngle+=curAngle;
 81
 82                    //标签
 83                    g.FillRectangle(new SolidBrush(GetColor(colorIndex)),boxOrigin.X,boxOrigin.Y,20,10);
 84                    g.DrawRectangle(Pens.Black,boxOrigin.X,boxOrigin.Y,20,10);
 85 
 86                    //说明
 87                    percent=Convert.ToSingle(row[dataColumn])/sumData*100;
 88                    g.DrawString(
 89                        row[descColumn].ToString()+"（"+percent.ToString("0.0")+"%）",
 90                        new Font("宋体",12),Brushes.Black,textOrigin
 91                        );
 92
 93                    boxOrigin.Y+=20;
 94                    textOrigin.Y+=20;
 95                }
 96            }
 97    
 98            //将生成的图保存到target
 99            bm.Save(targetFile,ImageFormat.Gif);
100 
101            //释放资源
102            bm.Dispose();
103            g.Dispose();
104        }
105
106        /**//// <summary>
107        /// 生成颜色的方法
108        /// </summary>
109        /// <param name="itemIndex"></param>
110        /// <returns></returns>
111        public static Color GetColor(int idx)
112        ...{
113            idx*=60;
114            int r=idx%255;
115            int g=((255/3)+idx)%255;
116            int b=((255*2/3)+idx)%255;
117            return Color.FromArgb(r,g,b);
118        }
119    }
120}