mvc实现图片验证码功能

mvc中实现图片验证码很简单，只需要创建一个 FileContentResult的方法，返回file就行

/// <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"); 

    }

以下是生成验证码代码：

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

  }
}

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