C# winform登陆框验证码的实现

1、验证码技术已愈来愈成熟，从最初的数字、字母、字符、汉字已经到目前的语言，其应用也甚广，之前大多数只有在网站上可以看到，现在在一些客户端软件也经常可见（比如证券相关软件）。之前做的一个基于 C# 客户端连 J2EE 应用的项目，其 Login Form 也要求实现验证码，在此贴上。1、 新建一个简单的 windows 应用项目在默认的 Form1 中添加如下控件：1） Label ： text = “ 输入验证码 :”2） TextBox ： name=” txtValidCode” 输入验证码的文本框3） Image ： name=” picValidCode” 显示验证码的图片控件4） Bu

2、tton ：单击事件进行验证码验证2、 新建一个产生验证码的核心类，并构建其一个实例： ValidCode validCode = new ValidCode (5, ValidCode .CodeType .Numbers)using System;using System.Text;using System.IO;using System.Drawing;namespace BigHorseLib.Securitypublic class ValidCode#region Private Fields/private readonly int _wordsLen = 4;private i

3、nt _len;private CodeType _codetype;private readonly Single _jianju = (float )18.0;private readonly Single _height = (float )24.0;private string _checkCode;#endregion#region Public Propertypublic string CheckCodegetreturn _checkCode;#endregion#region Constructors/ <summary>/ public constructors

4、/ </summary>/ <param name="len"> 验证码长度 </param>/ <param name="ctype"> 验证码类型：字母、数字、字母+ 数字 </param>public ValidCode(int len, CodeType ctype)this ._len = len;this ._codetype = ctype;#endregion#region Public Fieldpublic enum CodeType Words, Numbers, Char

5、acters, Alphas #endregion#region Private Methodsprivate string GenerateNumbers()string strOut = "" ;System.Random random = new Random ();for (int i = 0; i < _len; i+)string num = Convert .ToString(random.Next(10000)%10);strOut += num;return strOut.Trim();private string GenerateCharacter

6、s()string strOut = "" ;System.Random random = new Random ();for (int i = 0; i < _len; i+)string num = Convert .ToString(char )(65+random.Next(10000)%26);strOut += num;return strOut.Trim();/private string GenerateAlphas()string strOut = "" ;string num = "" ;System.Ran

7、dom random = new Random ();for (int i = 0; i < _len; i+)if (random.Next(500) % 2 = 0)num = Convert .ToString(random.Next(10000) % 10);elsenum = Convert .ToString(char )(65 + random.Next(10000) % 26);strOut += num;return strOut.Trim();/ 将位图背景填充为白色graph.Dispose();double dBaseAxisLen = bXDir ? (doub

8、le )destBmp.Height : (double )destBmp.Width;for (int i = 0; i < destBmp.Width; i+)for (int j = 0; j < destBmp.Height; j+)double dx = 0;dx = bXDir ? (PI2 * (double )j) / dBaseAxisLen : (PI2 * (double )i) / dBaseAxisLen;dx += dPhase;double dy = Math .Sin(dx);/ 取得当前点的颜色int nOldX = 0, nOldY = 0;nO

9、ldX = bXDir ? i + (int )(dy * dMultValue) : i;nOldY = bXDir ? j : j + (int )(dy * dMultValue);if (nOldX >= 0 && nOldX < destBmp.Width&& nOldY >= 0 && nOldY < destBmp.Height)destBmp.SetPixel(nOldX, nOldY, color);return destBmp;#endregion#region Public Methodspublic

10、 Stream CreateCheckCodeImage()string checkCode;switch (_codetype)case CodeType .Alphas:checkCode = GenerateAlphas();break ;case CodeType .Numbers:checkCode = GenerateNumbers();break ;case CodeType .Characters:checkCode = GenerateCharacters();break ;default :checkCode = GenerateAlphas();break ;this .

11、_checkCode = checkCode;MemoryStream ms = null ;/if (checkCode = null | checkCode.Trim() = String .Empty)return null ;Graphics g = Graphics .FromImage(image);tryRandom random = new Random ();g.Clear(Color .White);/ 画图片的背景噪音线for (int i = 0; i < 18; i+)int x1 = random.Next(image.Width);int x2 = rand

12、om.Next(image.Width);int y1 = random.Next(image.Height);int y2 = random.Next(image.Height);g.DrawLine(new Pen (Color .FromArgb(random.Next(),1), x1, y1, x2, y2);LinearGradientBrush brush = new LinearGradientBrush (new Rectangle (0, 0, image.Width, image.Height), Color .Blue, Color .DarkRed, 1.2f, tr

13、ue );if (_codetype != CodeType .Words)for (int i = 0; i < checkCode.Length; i+)g.DrawString(checkCode.Substring(i, 1), font, brush, 2 + i * _jianju,1);else g.DrawString(checkCode, font, brush, 2, 2);/ 画图片的前景噪音点for (int i = 0; i < 150; i+)int x = random.Next(image.Width);int y = random.Next(image.Height);image.SetPixel(x, y, Color .FromArgb(random.Next();/ 画图片的波形滤镜效果if (_codetype != CodeType .Words)image = TwistImage(image, true , 3, 1);/ 画图片的边框线g.DrawRectangle(new Pen (Color .Silver), 0, 0, image.Width - 1, image.Height -1);finallyg.Dispose();image.Di