asp.net图表统计类

using system;
using system.drawing;
using system.drawing.imaging;
using system.drawing.drawing2d;

namespace crystalreportsdemo
...{
    /**//// <summary>
    /// createreport绘制图形报表-柱图。
    /// </summary>
    public class createreport
    ...{

        public createreport()
        ...{
            //
            // todo: 在此处添加构造函数逻辑
            //
        }

        public bitmap createpicturereport(string[] x,int[] y,string reportname)
        ...{
            if(x.length != y.length)
            ...{
                throw new exception("x和y数目不一致");
            }
            int colnum=y.length;
            int colscale=880/(colnum+1);

            bitmap bmp = new bitmap(900,700,pixelformat.format24bpprgb);
            graphics dc = graphics.fromimage(bmp);
            dc.fillrectangle(new solidbrush(color.white),0,0,900,700);

            pen scalepen = new pen(color.black,2);
            pen gridpen = new pen(color.black,1);
       

            dc.drawline(scalepen,20,680,880,680);
            dc.drawline(scalepen,20,680,20,20);

            dc.drawline(gridpen,20,20,880,20);
            dc.drawline(gridpen,880,20,880,680);

            point drawpoint;
            int xpoint;
            int yheight;
            if(colnum==0)
            ...{
                throw new exception("无数据值,colnum值为0作为除数,抛出异常");
                    
            }
            int drawwidth=880/(4*colnum);
            //int drawwidth=580/(4*colnum+1);//4*colnum+1  确保colnum不为0.否则580/(4*0);的话会异常.0不能作为除数
            int maxnum=getmaxnum(y);
            rectangle rct;
            random rnd = new random();
            int red,green,blue;

            for(int i=20;i<680;i=i+96)
            ...{
                dc.drawline(gridpen,20,i,880,i);
            }

            for(int i=0;i<colnum;i++)
            ...{
                red=rnd.next(0,255);
                green=rnd.next(0,255);
                blue=rnd.next(0,255);
                solidbrush brush=new solidbrush(color.fromargb(red,green,blue));
                xpoint=20+((i+1)*colscale)-drawwidth;
                yheight=y[i]*650/maxnum;
                drawpoint=new point(xpoint,680-yheight);
                rct=new rectangle(drawpoint,new size(drawwidth*2,yheight));
                dc.fillrectangle(brush,rct);
                dc.drawrectangle(gridpen,rct);
           
                //绘制x数值
                dc.drawstring(x[i],new font("宋体",9),new solidbrush(color.orangered),new pointf((float)(xpoint+drawwidth/2),680-yheight/2));
                //绘制y数值
                dc.drawstring(y[i].tostring(), new font("宋体", 9), new solidbrush(color.black), new pointf((float)(xpoint + drawwidth / 2), 680 - yheight-15));
            }
           
           
            dc.drawstring(reportname,new font("宋体",10),brushes.black,3,3);
           
            return bmp;

            }
        private int getmaxnum(int[] arr)
        ...{
            int max=arr[0];
            for(int i=1;i<arr.length;i++)
            ...{
                if(arr[i]>max)
                ...{
                    max=arr[i];
                }

            }
            return max;
       
        }
   
    }
}