//用asp.net画拼图(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.ToInt32

total+=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"]),