用ashx一般处理程序创建验证码
1 <%@ WebHandler Language="C#" Class="ValidateCode" %> 2 using System; 3 using System.Web; 4 //下面是要使用到的命名空间 5 using System.Drawing; 6 using System.Drawing.Imaging; 7 using System.Drawing.Drawing2D; 8 using System.Web.SessionState; 9 public class ValidateCode : IHttpHandler, IRequiresSessionState//继承这个接口 10 { 11 public void ProcessRequest(HttpContext context) 12 { 13 context.Response.ContentType = "image/jpeg";//验证码图片的格式 14 string str = CreateCode(); 15 CreateStr(str);//将产生的随机数字，打印到画板上 16 } 17 Random random = new Random();//创建随机数对象 18 protected string CreateCode() 19 { 20 string randomStr = random.Next(1000, 10000).ToString();//产生一个四位的随机数 21 HttpContext.Current.Session["code"] = randomStr;//将产生的随机数赋值给Session 22 return randomStr; 23 } 24 protected void CreateStr(string code) 25 { 26 using (Bitmap map = new Bitmap(64, 30))//创建一张画板 27 { 28 using (Graphics gh = Graphics.FromImage(map))//为画板创建一个画笔 29 { 30 gh.Clear(Color.White);//填充背景色 31 //验证码边框 32 gh.DrawRectangle(new Pen(Color.Silver), 0, 0, map.Width - 1, map.Height - 1); 33 for (int i = 0; i < code.Length; i++) 34 { 35 Font font = new Font("黑体", 13.0f, FontStyle.Bold);//字体样式 36 Point pointStrat = new Point(0, 0);//线性渐变色的起始点 37 Point pointEnd = new Point(map.Width, map.Height);//线性渐变色的终止点 38 //线性渐变色:从红色过度到绿色 39 LinearGradientBrush brush = new LinearGradientBrush(pointStrat, pointEnd, Color.Red, Color.Green); 40 PointF pointF = new PointF(13.0f * i, random.Next(10));//数字在画板的随机位置 41 gh.DrawString(code.Substring(i, 1), font, brush, pointF);//设置随机数的属性 42 } 43 for (int i = 0; i < 5; i++)//干扰线 44 { 45 //干扰线的坐标 46 int x1 = random.Next(map.Width); 47 int x2 = random.Next(map.Height); 48 int y1 = random.Next(map.Width); 49 int y2 = random.Next(map.Height); 50 Color color = Color.FromArgb(random.Next(256), random.Next(256), random.Next(256));//干扰线的RGB颜色 51 gh.DrawLine(new Pen(color), x1, x2, y1, y2);//设置干扰线的随机颜色和坐标 52 } 53 for (int i = 0; i < 100; i++)//干扰点 54 { 55 //干扰点的坐标 56 int x = random.Next(map.Width); 57 int y = random.Next(map.Height); 58 Color color = Color.FromArgb(random.Next(256), random.Next(256), random.Next(256));//干扰点的RGB颜色 59 map.SetPixel(x, y, color);//设置干扰点的随机坐标和颜色 60 } 61 map.Save(HttpContext.Current.Response.OutputStream, ImageFormat.Jpeg);//保存验证码 62 } 63 } 64 } 65 public bool IsReusable 66 { 67 get 68 { 69 return false; 70 } 71 } 72 }
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验证码效果图:刷新页面验证码随机改变数字
