原文地址：http://www.cnblogs.com/tianguook/p/4142346.html
首先感谢aparche大牛的帖子，因为过两天可能要做个登录的页面，因此，需要用到验证码，从而看到了大神的这篇帖子，十分感谢。
产生验证码的类ValidCode
public class ValidCode { public enum CodeType { Words, Numbers, Characters, Alphas } private const double PI = 3.1415926535897932384626433832795; private const double PI2 = 6.283185307179586476925286766559; private int _len; private CodeType _codetype; private readonly Single _jianju = (float)18.0; private readonly Single _height = (float)24.0; private string _checkCode; public string CheckCode { get { return _checkCode; } } private string returnCode = ""; public string ReturnCode { get { return returnCode; } set { returnCode = value; } } /// <summary> /// 构造函数 /// </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; } private string GenerateNumbers() { Random random = new Random(); for (int i = 0; i < _len; i++) { string num = Convert.ToString(random.Next(10000) % 10); ReturnCode += num; } return ReturnCode.Trim(); } private string GenerateCharacters() { string num = ""; Random random = new Random(); for (int i = 0; i < _len; i++) { if (random.Next(500) % 2 == 0) { num = Convert.ToString((char)(65 + random.Next(10000) % 26)); } else { num = Convert.ToString((char)(97 + random.Next(10000) % 26)); } ReturnCode += num; } return ReturnCode.Trim(); } private string GenerateAlphas() { string num = ""; Random random = new Random(); for (int i = 0; i < _len; i++) { if (random.Next(500) % 3 == 0) { num = Convert.ToString(random.Next(10000) % 10); } else if (random.Next(500) % 3 == 1) { num = Convert.ToString((char)(65 + random.Next(10000) % 26)); } else { num = Convert.ToString((char)(97 + random.Next(10000) % 26)); } ReturnCode += num; } return ReturnCode.Trim(); } private Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase) { Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height); //将位图背景填充为白色 Graphics graph = Graphics.FromImage(destBmp); graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height); graph.Dispose(); double dBaseAxisLen = bXDir ? (double)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; nOldX = bXDir ? i + (int)(dy * dMultValue) : i; nOldY = bXDir ? j : j + (int)(dy * dMultValue); System.Drawing.Color color = srcBmp.GetPixel(i, j); if (nOldX >= 0 && nOldX < destBmp.Width && nOldY >= 0 && nOldY < destBmp.Height) { destBmp.SetPixel(nOldX, nOldY, color); } } } return destBmp; } public 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._checkCode = checkCode; MemoryStream ms = null; if (checkCode == null || checkCode.Trim() == string.Empty) return null; Bitmap image = new Bitmap((int)Math.Ceiling((checkCode.Length * _jianju)), (int)_height); Graphics g = Graphics.FromImage(image); try { Random 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 = random.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); } Font font = new Font("Times New Roman", 14, FontStyle.Bold); LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true); 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); ms = new MemoryStream(); image.Save(ms, ImageFormat.Gif); } finally { g.Dispose(); image.Dispose(); } return ms; } }修改内容如下：
1、大小写混合随机出现
原文都是用大写出现的，而我们常见的验证码都有大小写同时出现的情况，因此，在代码里多写了一句“num = Convert.ToString((char)(97 + random.Next(10000) % 26));”其中97是a的ASCII值。
2、增加一个返回的属性ReturnCode
原文在每段代码里都声明了一个strOut，而最后生成的是图片，如果再去解析图片的话，就得不偿失了，因此，增加一个属性，把相应的部分，进行替换，在调用的时候方便了取数。
调用页面的CS代码，写了一个MouseLeftButtonUp事件，可以在鼠标点击的时候，进行验证码变换。
public partial class MainWindow : Window { ValidCode validCode; public MainWindow() { InitializeComponent(); validCode = new ValidCode(4, ValidCode.CodeType.Alphas); image1.Source = BitmapFrame.Create(validCode.CreateCheckCodeImage()); } private void image1_MouseLeftButtonUp(object sender, MouseButtonEventArgs e) { validCode = new ValidCode(4, ValidCode.CodeType.Alphas); image1.Source = BitmapFrame.Create(validCode.CreateCheckCodeImage()); } private void btn1_Click(object sender, RoutedEventArgs e) { if (txtbox1.Text.ToUpper() == validCode.ReturnCode.ToUpper()) MessageBox.Show("输入验证码正确"); else MessageBox.Show("输入验证码错误"); } }实现效果图
原标题：WPF做验证码，小部分修改原作者内容
关键词：wpf
我知道了 