话不多说，直接上代码
public ValidateCode() { } ////// 验证码的最大长度 /// public int MaxLength { get { return 10; } } /// /// 验证码的最小长度 /// public int MinLength { get { return 1; } } /// /// 生成验证码 /// /// 指定验证码的长度 /// public string CreateValidateCode(int length) { int[] randMembers = new int[length]; int[] validateNums = new int[length]; string validateNumberStr = ""; //生成起始序列值 int seekSeek = unchecked((int)DateTime.Now.Ticks); Random seekRand = new Random(seekSeek); int beginSeek = (int)seekRand.Next(0, Int32.MaxValue - length * 10000); int[] seeks = new int[length]; for (int i = 0; i < length; i++) { beginSeek += 10000; seeks[i] = beginSeek; } //生成随机数字 for (int i = 0; i < length; i++) { Random rand = new Random(seeks[i]); int pownum = 1 * (int)Math.Pow(10, length); randMembers[i] = rand.Next(pownum, Int32.MaxValue); } //抽取随机数字 for (int i = 0; i < length; i++) { string numStr = randMembers[i].ToString(); int numLength = numStr.Length; Random rand = new Random(); int numPosition = rand.Next(0, numLength - 1); validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1)); } //生成验证码 for (int i = 0; i < length; i++) { validateNumberStr += validateNums[i].ToString(); } return validateNumberStr; } /// /// 创建验证码的图片 /// /// 要输出到的page对象 /// 验证码 public void CreateValidateGraphic(string validateCode, HttpContext context) { Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 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(validateCode, 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); //输出图片流 context.Response.Clear(); context.Response.ContentType = "image/jpeg"; context.Response.BinaryWrite(stream.ToArray()); } finally { g.Dispose(); image.Dispose(); } } /// /// 得到验证码图片的长度 /// /// 验证码的长度 /// public static int GetImageWidth(int validateNumLength) { return (int)(validateNumLength * 12.0); } /// /// 得到验证码的高度 /// /// public static double GetImageHeight() { return 22.5; } //C# MVC 升级版 /// /// 创建验证码的图片 /// /// 要输出到的page对象 /// 验证码 public byte[] CreateValidateGraphic(string validateCode) { Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 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(validateCode, 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); //输出图片流 return stream.ToArray(); } finally { g.Dispose(); image.Dispose(); } }
其中有两个根据数字和字母生成图片验证码的方法，相信大家能够明白，第一种是常规的WebForm后台调用的方法，可以i直接返回相应的验证码图片，第二种则是专门为ASP.NET准备的方法，其实就是筛检了一点东西，然后传入参数也发生了相应的变化，当然，还有点击“看不清，换一张”的时候，会异步获取新的数据，实现方法在文章末尾。
在MVC中的Controller中如下调用：
public ActionResult ShowVCode() { ValidateCode vliateCode = new ValidateCode(); string code = vliateCode.CreateValidateCode(4);//产生验证码 Session["validateCode"] = code; byte[] buffer = vliateCode.CreateValidateGraphic(code);//将验证码画到画布上. return File(buffer, "image/jpeg"); }
前台页面中如下调用：
验证码： "left"> "text" class="login-text" id="code" name="vCode" value="1" /> "imgCode" src="/Login/ShowVCode?id=2" style="float: left; height: 24px;" />
"float: left; margin-left: 5px; margin-top: 10px;"> "javascript:void(0)" οnclick="changeCheckCode();return false;">看不清，换一张
实现的效果如下图所示：
点击“看不清换一张”切换验证码代码如下：
如果对大家有帮助，希望点个赞 哈哈