后端开发|C#.Net教程
,生成,实现
后端开发-C#.Net教程生成验证码原理：产生随机字符，并将字符生成为图片，同时储存到Session里去，然后验证用户输入的内容是否与Session中的验证码相符即可。
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效果图：用户可以点击切换验证码信息。
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一般处理程序：CheckCodeHandler.cs
using System;using System.Web;using System.Text;using System.Drawing;using System.Web.SessionState;public class CheckCodeHandler : IHttpHandler,IRequiresSessionState{ //产生验证码的字符集 public string charcode = "2,3,4,5,6,8,9,A,B,C,D,E,F,G,H,J,K,M,N,P,R,S,U,W,X,Y,a,b,c,d,e,f,g,h,j,k,m,n,p,r,s,u,w,x,y"; public void ProcessRequest (HttpContext context) { string validateCode = CreateRandomCode(4); context.Session["ValidateCode"] = validateCode;//将验证码保存到session中 CreateCodeImage(validateCode, context); } public bool IsReusable { get {return false; } } /// /// 验证码个数 /// 验证码字符串 public string CreateRandomCode(int n) { string[] CharArray = charcode.Split(,);//将字符串转换为字符数组 string randomCode = ""; int temp = -1; Random rand = new Random(); for (int i = 0; i < n; i++) {if (temp != -1){ rand = new Random(i * temp * ((int)DateTime.Now.Ticks));}int t = rand.Next(CharArray.Length - 1);if (temp != -1 && temp == t){ return CreateRandomCode(n);}temp = t;randomCode += CharArray[t]; } return randomCode; } public void CreateCodeImage(string checkCode, HttpContext context) { int iwidth = (int)(checkCode.Length * 13); System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 20); Graphics g = Graphics.FromImage(image); Font f = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Italic | System.Drawing.FontStyle.Bold)); // 前景色 Brush b = new System.Drawing.SolidBrush(Color.Black); // 背景色 g.Clear(Color.White); // 填充文字 g.DrawString(checkCode, f, b, 0, 1); // 随机线条 Pen linePen = new Pen(Color.Gray, 0); Random rand = new Random(); for (int i = 0; i < 5; i++) {int x1 = rand.Next(image.Width);int y1 = rand.Next(image.Height);int x2 = rand.Next(image.Width);int y2 = rand.Next(image.Height);g.DrawLine(linePen, x1, y1, x2, y2); } // 随机点 for (int i = 0; i < 30; i++) {int x = rand.Next(image.Width);int y = rand.Next(image.Height);image.SetPixel(x, y, Color.Gray); } // 边框 g.DrawRectangle(new Pen(Color.Gray), 0, 0, image.Width - 1, image.Height - 1); // 输出图片 System.IO.MemoryStream ms = new System.IO.MemoryStream(); image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg); context.Response.ClearContent(); context.Response.ContentType = "image/jpeg"; context.Response.BinaryWrite(ms.ToArray()); g.Dispose(); image.Dispose(); }}
封装成类库：ValidateNumber.cs
using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Drawing;using System.Web.UI;using System.Drawing.Drawing2D;using System.IO;using System.Drawing.Imaging;/// public class ValidateNumber{ //产生验证码的字符集 （易混淆的字符去掉） private string charcode = "2,3,4,5,6,8,9,A,B,C,D,E,F,G,H,J,K,M,N,P,R,S,U,W,X,Y,a,b,c,d,e,f,g,h,j,k,m,n,p,r,s,u,w,x,y"; /// public int MaxLength { get { return 10; } } /// public int MinLength { get { return 1; } } /// /// 指定验证码的长度 /// public string CreateValidateNumber(int length) { string[] CharArray = charcode.Split(,);//将字符串转换为字符数组 string randomCode = ""; int temp = -1; Random rand = new Random(); for (int i = 0; i < length; i++) {if (temp != -1){ rand = new Random(i * temp * ((int)DateTime.Now.Ticks));}int t = rand.Next(CharArray.Length - 1);if (temp != -1 && temp == t){ return CreateValidateNumber(length);}temp = t;randomCode += CharArray[t]; } return randomCode; } /// /// context对象 /// 验证码 public void CreateValidateGraphic(HttpContext context,string validateNum) { int iwidth = (int)(validateNum.Length * 14); Bitmap image = new Bitmap(iwidth, 22); Graphics g = Graphics.FromImage(image); try {//生成随机生成器Random random = new Random();//清空图片背景色g.Clear(Color.White);//画图片的干扰线for (int i = 0; i < 25; i++){ int x1 = random.Next(image.Width); int x2 = random.Next(image.Width); int y1 = random.Next(image.Height); int y2 = random.Next(image.Height); g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);}Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic));LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);g.DrawString(validateNum, font, brush, 3, 2);//画图片的前景干扰点for (int i = 0; i < 100; i++){ int x = random.Next(image.Width); int y = random.Next(image.Height); image.SetPixel(x, y, Color.FromArgb(random.Next()));}//画图片的边框线g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);//保存图片数据MemoryStream stream = new MemoryStream();image.Save(stream, ImageFormat.Jpeg);//输出图片context.Response.Clear();context.Response.ContentType = "image/jpeg";context.Response.BinaryWrite(stream.ToArray()); } finally {g.Dispose();image.Dispose(); } } /// /// 验证码的长度 /// public static int GetImageWidth(int validateNumLength) { return (int)(validateNumLength * 14); } /// /// public static double GetImageHeight() { return 22; }}
