如何在C#的WinForm中制作饼状图和柱状图

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当我们的软件需要各种饼状图和柱状图来表示数据时，我们或许会想到用Offices中的图形控件或是第三方控件，但现在的第三方控件大都需要注册，有些免费的控件会有开发商的标记等。而对于使用Offices的图形控件来说，并不能在程序中得于很好控制，其使用的简易程度也较低，所以在这我给出在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。

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<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;
   }
   //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<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<Convert.ToSingle(dr[0]))
    {
     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<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);
    }
    //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<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;
    }
    //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;
}
}
}

以上是一个完整的WinForm中制作饼状图和柱状图源程序，大家可以通过以上程序的更改，做出能满足自己程序的需要。

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