當我們的軟件需要各種餅狀圖和柱狀圖來表示數據時，我們或許會想到用Offices中的圖形控件或是第三方控件，但現在的第三方控件大都需要注冊，有些免費的控件會有開發商的標記等。而對于使用Offices的圖形控件來說，并不能在程序中得于很好控制，其使用的簡易程度也較低，所以在這我給出在C#中使用GDI+實現餅狀圖和柱狀圖跟數據庫聯接顯示數據的方法。

using System;
using System.IO;//用于文件存取
using System.Data;//用于數據訪問
using System.Drawing;//提供畫GDI+圖形的基本功能
using System.Drawing.Text;//提供畫GDI+圖形的高級功能
using System.Drawing.Drawing2D;//提供畫高級二維，矢量圖形功能
using System.Drawing.Imaging;//提供畫GDI+圖形的高級功能
namespace BaseLayer
{
 public class PieChart
 {
  public PieChart()
  {
  }

//Render是圖形大標題，圖開小標題，圖形寬度，圖形長度，餅圖的數據集和餅圖的數據集要表示出來的數據

  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];
  
   //通過輸入參數，取得餅圖中的總基數
   float sumData = 0;
   foreach(DataRow dr in dt.Rows)
   {
    sumData += Convert.ToSingle(dr[DataLine]);
   }
   //產生一個image對象，并由此產生一個Graphics對象
   Bitmap bm = new Bitmap(width,height);
   Graphics g = Graphics.FromImage(bm);
   //設置對象g的屬性
   g.ScaleTransform((Convert.ToSingle(width))/SIDE_LENGTH,(Convert.ToSingle(height))/SIDE_LENGTH);
   g.SmoothingMode = SmoothingMode.Default;
   g.TextRenderingHint = TextRenderingHint.AntiAlias;
  
   //畫布和邊的設定
   g.Clear(Color.White);
   g.DrawRectangle(Pens.Black,0,0,SIDE_LENGTH-1,SIDE_LENGTH-1);
   //畫餅圖標題
   g.DrawString(title,new Font("Tahoma",14),Brushes.Black,new PointF(5,5));
   //畫餅圖的圖例
   g.DrawString(subTitle,new Font("Tahoma",12),Brushes.Black,new PointF(7,35));
   //畫餅圖
   float curAngle = 0;
   float totalAngle = 0;
   for(int i=0;i<dt.Rows.Count;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;
   }
   //畫圖例框及其文字
   g.DrawRectangle(Pens.Black,200,300,199,99);
   g.DrawString("圖表說明",new Font("Tahoma",12,FontStyle.Bold),Brushes.Black,new PointF(200,300));
  
   //畫圖例各項
   PointF boxOrigin = new PointF(210,330);
   PointF textOrigin = new PointF(235,326);
   float percent = 0;
   for(int i=0;i<dt.Rows.Count;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;
   }
   //回收資源
   g.Dispose();
   return (Image) bm;
  
  }
 }
  
 //畫條形圖
 public class BarChart
 {
  public BarChart()
  {
  }

//Render是圖形大標題，圖開小標題，圖形寬度，圖形長度，餅圖的數據集和餅圖的數據集
  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];
  
   //計算最高的點
   float highPoint = 0;
   foreach(DataRow dr in dt.Rows)
   {
    if(highPoint<Convert.ToSingle(dr[0]))
    {
     highPoint = Convert.ToSingle(dr[0]);
    }
   }
   //建立一個Graphics對象實例
   Bitmap bm = new Bitmap(width,height);
   try
   {
    Graphics g = Graphics.FromImage(bm);
    //設置條圖圖形和文字屬性
    g.ScaleTransform((Convert.ToSingle(width))/SIDE_LENGTH,(Convert.ToSingle(height))/SIDE_LENGTH);
    g.SmoothingMode = SmoothingMode.Default;
    g.TextRenderingHint = TextRenderingHint.AntiAlias;
  
    //設定畫布和邊
    g.Clear(Color.White);
    g.DrawRectangle(Pens.Black,0,0,SIDE_LENGTH-1,SIDE_LENGTH-1);
    //畫大標題
    g.DrawString(title,new Font("Tahoma",14),Brushes.Black,new PointF(5,5));
    //畫小標題
    g.DrawString(subTitle,new Font("Tahoma",12),Brushes.Black,new PointF(7,35));
    //畫條形圖
    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<dt.Rows.Count;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);
    }
    //設置邊
    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));
    //畫圖例框和文字
    g.DrawRectangle(new Pen(Color.Black,1),200,300,199,99);
    g.DrawString("圖表說明",new Font("Tahoma",12,FontStyle.Bold),Brushes.Black,new PointF(200,300));
  
    //畫圖例
    PointF boxOrigin = new PointF(210,330);
    PointF textOrigin = new PointF(235,326);
    for(int i=0;i<dt.Rows.Count;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;
    }
    //輸出圖形
    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;
  }
 }
}

以上是一個完整的WinForm中制作餅狀圖和柱狀圖源程序，大家可以通過以上程序的更改，做出能滿足自己程序的需要。