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。而對於使用Offices的圖形控件來說，並不能在程序中得於很好控制，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;//用於文件存取
using System.Data;//用於數據訪問
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，並由此產生一個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。
