C#中使用GDI+实现饼状图和柱状图跟数据库联接显示数据的方法.(其实也就是饼图的制作原理之一)

using System; 
using System.IO;//用于文件存取 
using System.Data;//用于数据访问 
using System.Drawing;//提供画GDI+图形的基本功能 
using System.Drawing.Text;//提供画GDI+图形的高级功能 
using System.Drawing.Drawing2D;//提供画高级二维，矢量图形功能 
using System.Drawing.Imaging;//提供画GDI+图形的高级功能 
namespace BaseLayer
{ 
 public class PieChart 
 { 
  public PieChart() 
  { 
  } 
//Render是图形大标题，图开小标题，图形宽度，图形长度，饼图的数据集和饼图的数据集要表示出来的数据
  public Image Render(string title, string subTitle, int width, int height, DataSet chartData,int DataLine) 
  { 
   const int SIDE_LENGTH = 400; 
   const int PIE_DIAMETER = 200; 
   DataTable dt = chartData.Tables[0]; 
   
   //通过输入参数，取得饼图中的总基数 
   float sumData = 0; 
   foreach(DataRow dr in dt.Rows) 
   { 
    sumData += Convert.ToSingle(dr[DataLine]); 
   } 
   //产生一个image对象，并由此产生一个Graphics对象 
   Bitmap bm = new Bitmap(width,height); 
   Graphics g = Graphics.FromImage(bm); 
   //设置对象g的属性 
   g.ScaleTransform((Convert.ToSingle(width))/SIDE_LENGTH,(Convert.ToSingle(height))/SIDE_LENGTH); 
   g.SmoothingMode = SmoothingMode.Default; 
   g.TextRenderingHint = TextRenderingHint.AntiAlias; 
   
   //画布和边的设定 
   g.Clear(Color.White); 
   g.DrawRectangle(Pens.Black,0,0,SIDE_LENGTH-1,SIDE_LENGTH-1); 
   //画饼图标题 
   g.DrawString(title,new Font("Tahoma",14),Brushes.Black,new PointF(5,5)); 
   //画饼图的图例 
   g.DrawString(subTitle,new Font("Tahoma",12),Brushes.Black,new PointF(7,35)); 
   //画饼图 
   float curAngle = 0; 
   float totalAngle = 0; 
   for(int i=0;i   { 
    curAngle = Convert.ToSingle(dt.Rows[i][DataLine]) / sumData * 360; 
   
    g.FillPie(new SolidBrush(ChartUtil.GetChartItemColor(i)),100,65,PIE_DIAMETER,PIE_DIAMETER,totalAngle,curAngle); 
    g.DrawPie(Pens.Black,100,65,PIE_DIAMETER,PIE_DIAMETER,totalAngle,curAngle); 
    totalAngle += curAngle; 
   } 
   //画图例框及其文字 
   g.DrawRectangle(Pens.Black,200,300,199,99); 
   g.DrawString("图表说明",new Font("Tahoma",12,FontStyle.Bold),Brushes.Black,new PointF(200,300)); 
   
   //画图例各项 
   PointF boxOrigin = new PointF(210,330); 
   PointF textOrigin = new PointF(235,326); 
   float percent = 0; 
   for(int i=0;i   { 
    g.FillRectangle(new SolidBrush(ChartUtil.GetChartItemColor(i)),boxOrigin.X,boxOrigin.Y,20,10); 
    g.DrawRectangle(Pens.Black,boxOrigin.X,boxOrigin.Y,20,10); 
    percent = Convert.ToSingle(dt.Rows[i][DataLine]) / sumData * 100; 
    g.DrawString(dt.Rows[i][1].ToString() + " - " + dt.Rows[i][0].ToString() + " (" + percent.ToString("0") + "%)",new Font("Tahoma",10),Brushes.Black,textOrigin); 
    boxOrigin.Y += 15; 
    textOrigin.Y += 15; 
   } 
   //回收资源 
   g.Dispose(); 
   return (Image) bm; 
   
  } 
 } 
   
 //画条形图 
 public class BarChart 
 { 
  public BarChart() 
  { 
  } 
//Render是图形大标题，图开小标题，图形宽度，图形长度，饼图的数据集和饼图的数据集
  public Image Render(string title, string subTitle, int width, int height, DataSet chartData) 
  { 
   const int SIDE_LENGTH = 400; 
   const int CHART_TOP = 75; 
   const int CHART_HEIGHT = 200; 
   const int CHART_LEFT = 50; 
   const int CHART_WIDTH = 300; 
   DataTable dt = chartData.Tables[0]; 
   
   //计算最高的点 
   float highPoint = 0; 
   foreach(DataRow dr in dt.Rows) 
   { 
    if(highPoint    { 
     highPoint = Convert.ToSingle(dr[0]); 
    } 
   } 
   //建立一个Graphics对象实例 
   Bitmap bm = new Bitmap(width,height); 
   try
   {
    Graphics g = Graphics.FromImage(bm); 
    //设置条图图形和文字属性 
    g.ScaleTransform((Convert.ToSingle(width))/SIDE_LENGTH,(Convert.ToSingle(height))/SIDE_LENGTH); 
    g.SmoothingMode = SmoothingMode.Default; 
    g.TextRenderingHint = TextRenderingHint.AntiAlias; 
   
    //设定画布和边 
    g.Clear(Color.White); 
    g.DrawRectangle(Pens.Black,0,0,SIDE_LENGTH-1,SIDE_LENGTH-1); 
    //画大标题 
    g.DrawString(title,new Font("Tahoma",14),Brushes.Black,new PointF(5,5)); 
    //画小标题 
    g.DrawString(subTitle,new Font("Tahoma",12),Brushes.Black,new PointF(7,35)); 
    //画条形图 
    float barWidth = CHART_WIDTH / (dt.Rows.Count * 2); 
    PointF barOrigin = new PointF(CHART_LEFT + (barWidth / 2),0); 
    float barHeight = dt.Rows.Count; 
    for(int i=0;i    { 
     barHeight = Convert.ToSingle(dt.Rows[i][0]) * 200 / highPoint * 1; 
     barOrigin.Y = CHART_TOP + CHART_HEIGHT - barHeight; 
     g.FillRectangle(new SolidBrush(ChartUtil.GetChartItemColor(i)),barOrigin.X,barOrigin.Y,barWidth,barHeight); 
     barOrigin.X = barOrigin.X + (barWidth * 2); 
    } 
    //设置边 
    g.DrawLine(new Pen(Color.Black,2),new Point(CHART_LEFT,CHART_TOP),new Point(CHART_LEFT,CHART_TOP + CHART_HEIGHT)); 
    g.DrawLine(new Pen(Color.Black,2),new Point(CHART_LEFT,CHART_TOP + CHART_HEIGHT),new Point(CHART_LEFT + CHART_WIDTH,CHART_TOP + CHART_HEIGHT)); 
    //画图例框和文字 
    g.DrawRectangle(new Pen(Color.Black,1),200,300,199,99); 
    g.DrawString("图表说明",new Font("Tahoma",12,FontStyle.Bold),Brushes.Black,new PointF(200,300)); 
   
    //画图例 
    PointF boxOrigin = new PointF(210,330); 
    PointF textOrigin = new PointF(235,326); 
    for(int i=0;i    { 
     g.FillRectangle(new SolidBrush(ChartUtil.GetChartItemColor(i)),boxOrigin.X,boxOrigin.Y,20,10); 
     g.DrawRectangle(Pens.Black,boxOrigin.X,boxOrigin.Y,20,10); 
     g.DrawString(dt.Rows[i][1].ToString() + " - " + dt.Rows[i][0].ToString(),new Font("Tahoma",10),Brushes.Black,textOrigin); 
     boxOrigin.Y += 15; 
     textOrigin.Y += 15; 
    } 
    //输出图形 
    g.Dispose(); 
    return bm;
   }
   catch
   {
    return bm;
   }   
  } 
 } 
 public class ChartUtil 
 { 
  public ChartUtil() 
  { 
  } 
  public static Color GetChartItemColor(int itemIndex) 
  { 
   Color selectedColor; 
   switch(itemIndex) 
   { 
    case 0: 
     selectedColor = Color.Blue; 
     break; 
    case 1: 
     selectedColor = Color.Red; 
     break; 
    case 2: 
     selectedColor = Color.Yellow; 
     break; 
    case 3: 
     selectedColor = Color.Purple; 
     break; 
    default: 
     selectedColor = Color.Green; 
     break; 
   } 
   return selectedColor; 
  } 
 } 
}