如何在C#的WinForm中制作饼状图和柱状图

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。