改编的图表控件，可以支持饼图，欢迎扩充

/**//// ///////////////////////////////////////////////////////////////////////
/// 控件说明：图表控件支持直线，矩形，饼图三种样式
///         Items:需要图像化的数据（传入DataTable）
///         Text:图表名称
///         DataStdName:标准值名称
///         DataName:对比值名称
///         ChatStyle :图表类型（ColumniationStyle）
///         Kddw：刻度单位，这里柱状图用的刻度单位是100
///         KdCount：刻度数，这里柱状图用的是5
/// 日期：20050623
/// 修改说明：from CNblogs
///////////////////////////////////////////////////////////////////////////

using System;
using System.Collections;
using System.Web.UI;
using System.Data;
using System.Web.UI.WebControls;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Web;
using System.ComponentModel;

[ assembly: TagPrefix("WebControl", "ci") ]
namespace WebControl
{
    public enum ColumniationStyle
    {
        histogram, beeline, caky
    }

    /**//// <summary>
    ///    柱状图控件
    ///    需要传入列表项名，值，超级连接地址
    /// </summary>
    [ToolboxData("<{0}:Columniation runat=server></{0}:Columniation>")]
    public class Columniation: System.Web.UI.WebControls.WebControl
    {
        private DataTable items;//列表项名称和值
       
        private string text="实时数据";
        private string datastd="标准值";
        private string data="实时数据";
        private ColumniationStyle _showType = ColumniationStyle.histogram;

        int kds=5; //刻度数
        int kddw=100;  //没刻度大小

        int zmheight=300; //真个图区高
        int zmwidth=640;  //真个图区宽

        int height=250;//呈现区高
        int width=530;
        int cxtop=30;//呈现区距顶距离
        int cxleft=30;//呈现区左边距离

        Color bzlink=Color.Black;//标准线颜色
        Color bz=Color.Coral;//标准柱颜色
        Color ss=Color.CornflowerBlue;//实时柱颜色

        //int cx=1;
    

        [Bindable(true),Category("Appearance"),DefaultValue("")]
        public string Text
        {
            get
            {
                return text;
            }

            set
            {
                text = value;
            }
        }
        
        [Bindable(true),Category("Appearance"),DefaultValue("")]
        public string DataStdName
        {
            get
            {
                return datastd;
            }

            set
            {
                datastd = value;
            }
        }

        [Bindable(true),Category("Appearance"),DefaultValue("")]
        public string DataName
        {
            get
            {
                return data;
            }

            set
            {
                data = value;
            }
        }

        /**//// <summary>
        /// 文本框中显示值还是名称。缺省显示值。
        /// </summary>
        [Bindable(true), Category("Schema"), DefaultValue(ColumniationStyle.histogram),
        Description("图表样式，默认为柱状图"), DesignOnly(true)]
        public ColumniationStyle ShowType
        {
            get
            {
                return this._showType ;
            }
            set
            {
                this._showType = value;
            }
        }    

        /**//// <summary>
        /// 需要呈现的数据
        /// </summary>
        public DataTable Items
        {
            set
            {items=value;}
        }

        /**//// <summary>
        /// 需要显示的刻度量
        /// </summary>
        public int Kdcount
        {
            set {kds=value;}
        }

        /**//// <summary>
        /// 刻度大小
        /// </summary>

        public int Kddw
        {set{kddw=value;}}
        


        public ColumniationStyle ChatStyle
        {set{this._showType=value;}}


        /**//// <summary> 
        /// 将此控件呈现给指定的输出参数。
        /// </summary>
        /// <param text="output"> 要写出到的 HTML 代码 </param>
        protected override void Render(HtmlTextWriter output)
        {
            //设计样式
            output.Write(makeimage(items,@"c:/"));
            
        }

        private string makeimage(DataTable dt,string imagefile)
        {
            if(dt==null)
            {
                return "没有数据";
            }

            //调整宽度
            width=30*dt.Rows.Count+10;
            zmwidth=width+cxleft+80;
            //Font
            Font fontlegend = new Font("verdana",9);
            //创建一个画布
            Bitmap bm=new Bitmap(zmwidth,zmheight);
            //在新建的画布上画一个图
            Graphics bp=Graphics.FromImage(bm);
            //填充背景
            bp.Clear(Color.White);
            //填充图表呈现区背景(画刷,起点x，起点Y，高，宽)
            bp.FillRectangle(new SolidBrush(Color.WhiteSmoke),cxleft,cxtop,width,height);
            //描绘呈现区边框
            bp.DrawRectangle(Pens.Black,cxleft,cxtop,width,height);
            //绘制图表名称
            bp.DrawString(text,fontlegend,new SolidBrush(Color.Black),new PointF(zmwidth/2,10));
            
            if(this._showType!=ColumniationStyle.caky)
            {
                //绘制图表说明
                bp.DrawRectangle(Pens.Black,cxleft+width+10,zmheight/2,60,30);
                //标准图例
                bp.FillRectangle(new SolidBrush(bz),cxleft+width+10+2,zmheight/2+4,8,8);
                //文字说明
                bp.DrawString(datastd,fontlegend,new SolidBrush(Color.Black),new PointF(cxleft+width+10+2+8,zmheight/2+4));
                //实时图例
                bp.FillRectangle(new SolidBrush(ss),cxleft+width+10+2,zmheight/2+16,8,8);
                //文字说明
                bp.DrawString(data,fontlegend,new SolidBrush(Color.Black),new PointF(cxleft+width+10+2+8,zmheight/2+16));
                //通过循环绘制标准线
                for(int i=1;i<=kds;i++)
                {
                    if(i*bl(kddw)>height)
                    {break;}
                    //绘制刻度名
                    bp.DrawString(System.Convert.ToString((i*kddw)),fontlegend,new SolidBrush(Color.Black),new PointF(2,zmheight-(bl(i*kddw)+(zmheight-cxtop-height)+4)));
                    //填充标准线(画刷，起点Ｘ，起点Ｙ，宽，高）
                    int top=zmheight-((int)bl(i*kddw)+(zmheight-cxtop-height));
                    bp.DrawLine(new Pen(bzlink),new Point(cxleft-4,top),new Point(cxleft+width,top));
                }
            }
            
            switch(this._showType)
            {
                case ColumniationStyle.histogram:
                {
                    柱状图#region  柱状图
                    //通过循环画出柱状图
                    for(int i=0;i<dt.Rows.Count;i++)
                    {   
                        //标准刻度
                        float bzkd=bl(Convert.ToSingle(dt.Rows[i].ItemArray[1]));
                        //实际刻度
                        float sjkd=bl(Convert.ToSingle(dt.Rows[i].ItemArray[2]));
                        int top=zmheight-(int)bzkd-(zmheight-cxtop-height);
                        //填充标准柱(画刷，起点Ｘ，起点Ｙ，宽，高）
                        bp.FillRectangle(new SolidBrush(bz),(i*30)+cxleft+10,top,10,bzkd);
                        top=zmheight-(int)sjkd-(zmheight-cxtop-height);
                        bp.FillRectangle(new SolidBrush(ss),(i*30)+cxleft+20,top,10,sjkd);
                
                        //填充项目名称(输出文字,字体，画刷，位置)
                        bp.DrawString(dt.Rows[i].ItemArray[0].ToString(),fontlegend,new SolidBrush(Color.Black),new PointF((i*30)+cxleft+5,height+cxtop+1));
                
                    }
                    #endregion
                    break;
                }
                case ColumniationStyle.beeline:
                {
                    曲线#region  曲线
                    //通过循环画出曲线图   
                    int x=-1;
                    int bzy=-1;
                    int ssy=-1;
                    for(int i=0;i<dt.Rows.Count;i++)
                    {   
               
                        //标准刻度
                        float bzkd=bl(Convert.ToSingle(dt.Rows[i].ItemArray[1]));
                        //实际刻度
                        float sjkd=bl(Convert.ToSingle(dt.Rows[i].ItemArray[2]));
                        int bztop=zmheight-(int)bzkd-(zmheight-cxtop-height)-3;
                        //填充标准柱(画刷，起点Ｘ，起点Ｙ，宽，高）
                        bp.FillRectangle(new SolidBrush(bz),(i*30)+cxleft,bztop,6,6);
                        int sstop=zmheight-(int)sjkd-(zmheight-cxtop-height)-3;
                        //填充实时点(画刷，起点Ｘ，起点Ｙ，宽，高）
                        bp.FillRectangle(new SolidBrush(ss),(i*30)+cxleft,sstop,6,6);
                    
                        //绘制点到点连接线
                        if(x!=-1)
                        {
                            //绘制标准点连接线
                            bp.DrawLine(new Pen(bz,1.6F),new Point(x-3,bzy+4),new Point((i*30)+cxleft+10,bztop+4));
                            //绘制实时点连接线
                            bp.DrawLine(new Pen(ss,1.6F),new Point(x+3,ssy+4),new Point((i*30)+cxleft+10,sstop+4));
                        }
                        x=(i*30)+cxleft+10;
                        bzy=bztop;
                        ssy=sstop;
                    }
                    #endregion
                    break;
                }
                case ColumniationStyle.caky:
                {
                    饼图#region 饼图
                    float currentdegree=0.0f;
                    
                    StringFormat stringFormat = new StringFormat();
                    stringFormat.Alignment = StringAlignment.Near;
                    stringFormat.LineAlignment = StringAlignment.Center;
                    
                    Hashtable arlNum = new Hashtable();    
                    float total = 0;    

                    SolidBrush blackbrush=new SolidBrush(Color.Black);
                    
                    for(int i=0;i<dt.Rows.Count;i++)
                    {  
                        arlNum.Add(i, dt.Rows[i].ItemArray[1]);
                        total += Convert.ToInt32(dt.Rows[i].ItemArray[1]);
                    }

                    Rectangle pierect = new Rectangle(cxleft+width/6,cxtop, height-20, height-20);

                    int eHeight = 12;
                    int TitleX = cxleft+width/2+width/4;
                    int TitleY = 0;    
                    foreach(DictionaryEntry ht in arlNum)
                    {
                        SolidBrush brush = new SolidBrush(PieColor(Convert.ToInt32(ht.Key)));

                        //******画扇形图及其中的百分比********//
                        bp.FillPie(brush, pierect, currentdegree,Convert.ToSingle(ht.Value) / total * 360);
                            
                        currentdegree += Convert.ToSingle(ht.Value) / total * 360;

                        //示例图(画刷，起点Ｘ，起点Ｙ，宽，高）
                        TitleY = cxtop+Convert.ToInt32(ht.Key)*eHeight;
                        bp.FillRectangle(brush,TitleX,TitleY+4,50,16);
                        bp.DrawRectangle(Pens.Black,TitleX,TitleY+4,50,16);
                        //Font
                        string sfont = Convert.ToString(Math.Round(Convert.ToDecimal(Convert.ToInt32(ht.Value) * 100 / total),2)) + "%";
                        bp.DrawString(sfont, fontlegend, blackbrush,new PointF(TitleX+2,TitleY+14), stringFormat);
                        bp.DrawString(dt.Rows[Convert.ToInt32(ht.Key)][0].ToString(), fontlegend, blackbrush,new PointF(TitleX+54,TitleY+14), stringFormat);
                    
                    }
                    #endregion
                    break;
                }

            }
                
            
            FileStream fs=new FileStream(Page.Server.MapPath(Page.Request.Url.AbsolutePath.Replace(".aspx",".jpg")),FileMode.Create);
            bm.Save(fs,ImageFormat.Jpeg);

            bm.Dispose();
            bp.Dispose();
            fs.Close();
                    
            return "<img src="+Page.Request.Url.AbsolutePath.Replace(".aspx",".jpg")+" ></img>";
    
        }


        private Color PieColor(int intColor)
        {
            switch(intColor)
            {
                case 1:
                    return Color.Blue;
                case 2:
                    return Color.Green;
                case 3:
                    return Color.GreenYellow;
                case 4:
                    return Color.Red;
                case 5:
                    return Color.Brown;
                case 6:
                    return Color.DarkGray;
                case 7:
                    return Color.Salmon;
                case 8:
                    return Color.Plum;
                case 9:
                    return Color.SkyBlue;
                case 10:
                    return Color.AliceBlue;
                case 11:
                    return Color.AntiqueWhite;
                case 12:
                    return Color.Aquamarine;
                case 13:
                    return Color.Azure;
                case 14:
                    return Color.Beige;
                case 15:
                    return Color.Bisque;
                case 16:
                    return Color.BlanchedAlmond;
                case 17:
                    return Color.BlueViolet;
                case 18:
                    return Color.BurlyWood;
                case 19:
                    return Color.CadetBlue;
                case 20:
                    return Color.Chartreuse;
                default:
                    return Color.Moccasin;
            }
        }


        /**//// <summary>
        /// 换算成实际值
        /// </summary>
        /// <param text="kd">提供的值</param>
        /// <returns>返回换算后的实际值</returns>
        private float bl(float kd)
        {
            float bls=1;
            bls=(float)height/((float)kds*(float)kddw);
            return (float)kd*bls;
        }

    }

}

效果：

di
调用示例：

        private void ShowData()
        {
            DataTable dt=new DataTable();
            
            
            dt.Columns.AddRange(new DataColumn[]{new DataColumn("name",typeof(string)),
                                                    new DataColumn("bz",typeof(Decimal)),
                                                    new DataColumn("db",typeof(Decimal))
                                                
                                                });
            
            DataRow dr=dt.NewRow();
            
            dr["name"]="点1";
            dr["bz"]="100";
            dr["db"]="150";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点2";
            dr["bz"]="110";
            dr["db"]="200";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点3";
            dr["bz"]="120";
            dr["db"]="300";
            dt.Rows.Add(dr);

            
            dr=dt.NewRow();
            dr["name"]="点4";
            dr["bz"]="130";
            dr["db"]="250";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点5";
            dr["bz"]="140";
            dr["db"]="400";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点6";
            dr["bz"]="150";
            dr["db"]="375";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点7";
            dr["bz"]="160";
            dr["db"]="437";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点8";
            dr["bz"]="170";
            dr["db"]="340";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点9";
            dr["bz"]="180";
            dr["db"]="50";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点10";
            dr["bz"]="190";
            dr["db"]="460";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点11";
            dr["bz"]="200";
            dr["db"]="150";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点12";
            dr["bz"]="210";
            dr["db"]="200";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点13";
            dr["bz"]="220";
            dr["db"]="300";
            dt.Rows.Add(dr);

            
            dr=dt.NewRow();
            dr["name"]="点14";
            dr["bz"]="230";
            dr["db"]="250";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点15";
            dr["bz"]="240";
            dr["db"]="400";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点16";
            dr["bz"]="250";
            dr["db"]="375";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点17";
            dr["bz"]="260";
            dr["db"]="437";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点18";
            dr["bz"]="270";
            dr["db"]="340";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点19";
            dr["bz"]="280";
            dr["db"]="50";
            dt.Rows.Add(dr);

            dr=dt.NewRow();
            dr["name"]="点20";
            dr["bz"]="290";
            dr["db"]="460";
            dt.Rows.Add(dr);

    
            Columniation1.Items =dt;
            Columniation1.Kddw = 100;
            Columniation1.Kdcount = 5;
            Columniation1.ChatStyle=this.style;
            //string path=@"c:/";
            //DIV1.InnerHtml = this.makeimage(dt,path);

        }