<img id="vcodeimg" src="/Home/VCode" width="70"                                     height="25" />                                  <span                                     style="cursor: pointer; text-decoration: underline">换一张</span>

using System; using System.Collections.Generic; using System.Linq; using System.Web; using System.Web.Mvc; using Utility; using Jellal**; namespace sjlwebsite.Controllers {     public class CommonController : Controller     {         #region 验证码         [OutputCache(Duration = 0)]         public ActionResult VCode()         {             string code = ValidateCode.CreateRandomCode(4);             Session["vcode"] = code;             ValidateCode.CreateImage(code);             return View();         }         public string GetCode()         {             return Session["vcode"].ToStr();         }         #endregion     } }

using System; using System.Collections; using System.ComponentModel; using System.Data; using System.Drawing; using System.Web; using System.Web.SessionState; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.HtmlControls; namespace Utility {     ///  <summary>      ///  完美随机验证码  0.10      ///  Verion:0.10      ///  Description:随机生成设定验证码，并随机旋转一定角度，字体颜色不同      ///  </summary>      public class ValidateCode     {         ///  <summary>          ///  生成随机码          ///  </summary>          ///  <param  name="length">随机码个数www.52mvc.com</param>          ///  <returns></returns>          public static string CreateRandomCode(int length)         {             int rand;             char code;             string randomcode = String.Empty;             //生成一定长度的验证码              System.Random random = new Random();             for (int i = 0; i < length; i++)             {                 rand = random.Next();                 if (rand % 3 == 0)                 {                     code = (char)('A' + (char)(rand % 26));                 }                 else                 {                     code = (char)('0' + (char)(rand % 10));                 }                 randomcode += code.ToString();             }             return randomcode;         }         ///  <summary>          ///  创建随机码图片          ///  </summary>          ///  <param  name="randomcode">随机码</param>          public static void CreateImage(string randomcode)         {             int randAngle = 45; //随机转动角度              int mapwidth = (int)(randomcode.Length * 23);             Bitmap map = new Bitmap(mapwidth, 28);//创建图片背景              Graphics graph = Graphics.FromImage(map);             graph.Clear(Color.AliceBlue);//清除画面，填充背景              graph.DrawRectangle(new Pen(Color.Black, 0), 0, 0, map.Width - 1, map.Height - 1);//画一个边框              //graph.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.AntiAlias;//模式              Random rand = new Random();             //背景噪点生成    www.1sucai.cn             Pen blackPen = new Pen(Color.LightGray, 0);             for (int i = 0; i < 50; i++)             {                 int x = rand.Next(0, map.Width);                 int y = rand.Next(0, map.Height);                 graph.DrawRectangle(blackPen, x, y, 1, 1);             }             //验证码旋转，防止机器识别                char[] chars = randomcode.ToCharArray();//拆散字符串成单字符数组              //文字距中              StringFormat format = new StringFormat(StringFormatFlags.NoClip);             format.Alignment = StringAlignment.Center;             format.LineAlignment = StringAlignment.Center;             //定义颜色              Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };             //定义字体              string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };             for (int i = 0; i < chars.Length; i++)             {                 int cindex = rand.Next(7);                 int findex = rand.Next(5);                 Font f = new System.Drawing.Font(font[findex], 13, System.Drawing.FontStyle.Bold);//字体样式(参数2为字体大小)                  Brush b = new System.Drawing.SolidBrush(c[cindex]);                 Point dot = new Point(16, 16);                 //graph.DrawString(dot.X.ToString(),fontstyle,new SolidBrush(Color.Black),10,150);//测试X坐标显示间距的                  float angle = rand.Next(-randAngle, randAngle);//转动的度数                  graph.TranslateTransform(dot.X, dot.Y);//移动光标到指定位置                  graph.RotateTransform(angle);                 graph.DrawString(chars.ToString(), f, b, 1, 1, format);                 //graph.DrawString(chars.ToString(),fontstyle,new SolidBrush(Color.Blue),1,1,format);                  graph.RotateTransform(-angle);//转回去                  graph.TranslateTransform(2, -dot.Y);//移动光标到指定位置              }             //graph.DrawString(randomcode,fontstyle,new SolidBrush(Color.Blue),2,2); //标准随机码              //生成图片              System.IO.MemoryStream ms = new System.IO.MemoryStream();             map.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);             HttpContext.Current.Response.ClearContent();             HttpContext.Current.Response.ContentType = "image/gif";             HttpContext.Current.Response.BinaryWrite(ms.ToArray());             graph.Dispose();             map.Dispose();         }     } }