mvc实现图片验证码功能

/// <summary>    /// 创建一个文件方法    /// </summary>    /// <returns></returns>    public FileContentResult GetCode() {      //参数一：产生几个字符的验证码图片 参数二：验证码的形式(数字、字母、数字字母混合都有)      ValidateCode validCode = new ValidateCode(5, ValidateCode.CodeType.Alphas);        //将图片转换为二进制      MemoryStream ms =validCode.CreateCheckCodeImage() as MemoryStream;        dateCode = validCode.CheckCode; //通过 CheckCode获取当前的验证码      byte[] buffurPic = ms.ToArray();       return File(buffurPic, "image/jpeg");       }

using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks; using System.Drawing;using System.Drawing.Drawing2D;using System.IO; namespace Helper{  public class ValidateCode  {     #region Private Fields    private const double PI = 3.1415926535897932384626433832795;    private const double PI2 = 6.283185307179586476925286766559;    //private readonly int _wordsLen = 4;    private int _len;   private CodeType _codetype;   private readonly Single _jianju = (float)18.0;    private readonly Single _height = (float)24.0;    private string _checkCode;    #endregion    #region Public Property    public string CheckCode   {      get     {        return _checkCode;      }    }    #endregion    #region Constructors    ///     /// public constructors    ///    /// 验证码长度     /// 验证码类型：字母、数字、字母+ 数字     public ValidateCode(int len, CodeType ctype)   {      this._len = len;      this._codetype = ctype;    }    #endregion    #region Public Field    public enum CodeType { Words, Numbers, Characters, Alphas }    #endregion    #region Private Methods    public 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();    }      public string GenerateCharacters()   {      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();    }    //     public string GenerateAlphas()   {     string strOut = "";      string num = "";      System.Random random = new Random();     for (int i = 0; i < _len; i++)     {        if (random.Next(500) % 2 == 0)       {          num = Convert.ToString(random.Next(10000) % 10);        }        else       {          num = Convert.ToString((char)(65 + random.Next(10000) % 26));        }        strOut += num;      }      return strOut.Trim();    }      private System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)   {      System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);      // 将位图背景填充为白色      System.Drawing.Graphics graph = System.Drawing.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;    }    #endregion    #region Public Methods    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 System.Drawing.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 System.Drawing.Font("Times New Roman", 14, System.Drawing.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 System.IO.MemoryStream();        image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);      }      finally     {        g.Dispose();        image.Dispose();      }      return ms;    }    #endregion      }}