用asp.net画饼图

//用asp.net画饼图(可用于各种投票程序)//和asp相比asp.net拥有更强大的功能，使用gdi+可以轻易实现以前很多不能办到的图形功能。//首先在c:/中建库mess.mdb,并建表title.//建二个字段,title(char型),point(int型)//非常满意;;;;;281//比较满意;;;;;297//还凑合;166//不满意;416//我还写了画折线图和条形图的部分,目前正在把它们全部写进一个类中。需要的可以和我联系:mailto:ouyang76@263.net<%@ Page Language="C#" %><%@import namespace="System.Data"%><%@import namespace="System.Data.OleDb"%><%@import namespace="System.Drawing"%><%@import namespace="System.Drawing.Imaging"%><script language="c#" runat="server">public void page_load(Object obj,EventArgs e) {//把连接字串指定为一个常量const String strconn = "Provider=Microsoft.Jet.OLEDB.4.0;" + "Data Source=c://mess.mdb";OleDbConnection conn=new OleDbConnection(strconn);conn.Open();string sql="select *;;from title";OleDbCommand cmd=new OleDbCommand(sql,conn);DataSet ds=new DataSet();OleDbDataAdapter adapter1=new OleDbDataAdapter(cmd);adapter1.Fill(ds);conn.Close();float total=0.0f,tmp;int iloop; for(iloop=0;iloop<ds.Tables[0].Rows.Count;iloop++){tmp=Convert.ToSingle(ds.Tables[0].Rows[iloop]["point"]);//转换成单精度,投票不可能投半票。也可写成Convert.ToInt32total+=tmp;}//Response.Write(Convert.ToString(total));Font fontlegend=new Font("verdana",9),fonttitle=new Font("verdana",10,FontStyle.Bold);//设置字体//fonttitle为主标题的字体int width=230;//白色背景宽const int bufferspace=15;int legendheight=fontlegend.Height*(ds.Tables[0].Rows.Count+1)+bufferspace; int titleheight = fonttitle.Height + bufferspace; int height = width + legendheight + titleheight + bufferspace;//白色背景高 int pieheight = width;Rectangle pierect=new Rectangle(0,titleheight,width,pieheight);//加上各种随机色 ArrayList colors = new ArrayList(); Random rnd = new Random(); for (iloop = 0; iloop < ds.Tables[0].Rows.Count; iloop++)colors.Add(new SolidBrush(Color.FromArgb(rnd.Next(255), rnd.Next(255), rnd.Next(255))));Bitmap objbitmap=new Bitmap(width,height);//创建一个bitmap实例//Bitmap objbitmap=new Bitmap(230,500);//创建一个bitmap实例Graphics objgraphics=Graphics.FromImage(objbitmap);objgraphics.FillRectangle(new SolidBrush(Color.White), 0, 0, width, height);//画一个白色背景objgraphics.FillRectangle(new SolidBrush(Color.LightYellow), pierect);//画一个亮黄色背景//以下为画饼图(有几行row画几个)float currentdegree=0.0f; for (iloop = 0; iloop < ds.Tables[0].Rows.Count; iloop++) {objgraphics.FillPie((SolidBrush) colors[iloop], pierect, currentdegree,Convert.ToSingle(ds.Tables[0].Rows[iloop]["point"]) / total * 360);currentdegree += Convert.ToSingle(ds.Tables[0].Rows[iloop]["point"]) / total * 360; }//---以下为生成主标题SolidBrush blackbrush=new SolidBrush(Color.Black);string title="本次《程序员大本营》推出了配套的专刊，您对专刊满意吗？"; StringFormat stringFormat = new StringFormat(); stringFormat.Alignment = StringAlignment.Center; stringFormat.LineAlignment = StringAlignment.Center; objgraphics.DrawString(title, fonttitle, blackbrush, new Rectangle(0, 0, width, titleheight), stringFormat);//列出各字段与得票数objgraphics.DrawRectangle(new Pen(Color.Black, 2), 0, height - legendheight, width, legendheight);for (iloop = 0; iloop < ds.Tables[0].Rows.Count; iloop++){objgraphics.FillRectangle((SolidBrush) colors[iloop], 5, height - legendheight + fontlegend.Height * iloop + 5, 10, 10);objgraphics.DrawString(((String) ds.Tables[0].Rows[iloop]["title"]) + " - " + Convert.ToString(ds.Tables[0].Rows[iloop]["point"]), fontlegend, blackbrush, 20, height - legendheight + fontlegend.Height * iloop + 1);}//objgraphics.DrawString("总票数是:"+Convert.ToString(total),fontlegend,blackbrush, 5, height - fontlegend.Height );//图像总的高度-一行字体的高度，即是最底行的一行字体高度(height - fontlegend.Height )Response.ContentType="image/jpeg";objbitmap.Save(Response.OutputStream,ImageFormat.Jpeg);//objbitmap.Save("myyyyyyyyyyy.jpg", ImageFormat.Jpeg);//输出到文件objgraphics.Dispose();objbitmap.Dispose();}</script>