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DrawingOnWebPage.ashx页
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using System;
using System.Collections;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Xml.Linq;
using System.Drawing.Drawing2D;
using System.Drawing;
namespace AspTechnicalBase
{
??? /// <summary>
??? /// $codebehindclassname$ 的摘要说明
??? /// </summary>
??? [WebService(Namespace = "http://tempuri.org/")]
??? [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
??? public class DrawingOnWebPage : IHttpHandler
??? {??? /// <summary>
??????? /// 绘图的相关参数
??????? /// </summary>
??????? private const int ImageWidth = 600;? //指定验证码的宽度
??????? private const int ImageHeight = 100; //指定验证的高度
??????? private const int codeLength = 4;// 指定生成几个验证码
??????? /// <summary>
??????? /// 响应HTTP请求
??????? /// </summary>
??????? /// <param name="context">HTTP请求的上下文对象</param>
??????? public void ProcessRequest(HttpContext context)
??????? {
??????????? string str = createCode( codeLength ) as string;
??????????? //开辟一个ImageWidth像素宽、ImageHeight像素高的绘图缓冲区
??????????? Bitmap bmp = new Bitmap(ImageWidth,ImageHeight);
??????????? //创建绘图表面对象，引用这一绘图缓冲区
??????????? Graphics g = Graphics.FromImage(bmp);
??????????? //生成一个渐变的画刷
??????????? Brush br = new LinearGradientBrush(new Point(0,0),new Point(ImageWidth,Color.Black,Color.Blue);
??????????? //用渐变画刷填充绘图表面
??????????? g.FillRectangle(br,g.ClipBounds);
???????????
??????????? Font f = new Font("宋体",30);
??????????? //输出文字
??????????? g.DrawString(str,f,Brushes.Yellow,new PointF(40,20));
??????????? //将结果输出到浏览器
??????????? context.Response.ContentType = "Image/JPEG";
??????????? context.Response.Clear();
??????????? context.Response.BufferOutput = true;
??????????? bmp.Save(context.Response.OutputStream,System.Drawing.Imaging.ImageFormat.Jpeg);
??????????? //释放相关的绘图对象
??????????? br.Dispose();
??????????? f.Dispose();
??????????? g.Dispose();
??????????? bmp.Dispose();
??????? }
??????? /// <summary>
??????? /// 是否自动缓存此对象以供下次复用
??????? /// </summary>
??????? ///
??????? private string createCode( int codeLength )
??????? {
??????????? string so = "1,2,3,4,5,6,7,8,9,a,b,c,d,e,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,V,W,X,Y,Z";
??????????? string[] strArr = so.Split(',');
??????????? string code = "";
??????????? Random rand = new Random();
??????????? for (int i = 0; i < codeLength; i++)
??????????? {
??????????????? code += strArr[rand.Next(0,strArr.Length)];
??????????? }
??????????? return code;
??????? }
???????
??????? public bool IsReusable
??????? {
??????????? get
??????????? {
??????????????? return false;
??????????? }
??????? }
??? }
}
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然后是显示验证码的页面 的html中加入<img src="DrawingOnWebPage.ashx"? id="poloy" alt="点击刷新"? /> 在</head>之前一行加入javascript脚本语言如下(当然写在JS文件里面更好): <script type="text/javascript"> function reloadcode(){ document.getElementById("poloy").src ="DrawingOnWebPage.ashx"; } </script>
