C# winform登陆框验证码的实现方法

本文实例为大家分享了C# winform登陆框验证码的具体代码，供大家参考，具体内容如下

1、新建一个简单的 windows 应用项目

在默认的 Form1 中添加如下控件：

1） Label ： text = “ 输入验证码 :”

2） TextBox ： name=” txtValidCode” 输入验证码的文本框

3） Image ： name=” picValidCode” 显示验证码的图片控件

4） Button ：单击事件进行验证码验证

2、新建一个产生验证码的核心类，并构建其一个实例：

ValidCode validCode = new ValidCode (5,ValidCode .CodeType .Numbers)

				?

									using System;

									using System.Collections.Generic;

									using System.Text;

									using System.IO;

									using System.Drawing;

									using System.Drawing.Drawing2D;

									namespace BigHorseLib.Security

									{

									  public class ValidCode

									  {

									    #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

									    /// <summary>

									    /// public constructors

									    /// </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;

									    }

									    #endregion

									    #region Public Field

									     public enum CodeType {Words, Numbers, Characters, Alphas }

									    #endregion

									    #region Private Methods

									    private 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();

									    }

									    private 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();

									    }

									    //

									    private 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

									  }

									}

3、图片加载验证码、验证码验证

				?

									// 图片加载验证码

									picValidCode.Image = Bitmap .FromStream(validCode.CreateCheckCodeImage())

									// 验证

									  if (!this .txtValidCode.Text.Equals(_validCode.CheckCode))

									   {

									     MessageBox .Show(" 请输入正确的验证码!" , this .Text);

									     this .txtValidCode.Focus();

									     return ;

									 }