本文实例讲述了WinForm生成验证码图片的方法。分享给大家供大家参考，具体如下：
1、创建ValidCode类：
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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
}
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2、产生验证码图片代码：
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//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)
ValidCode validCode = new ValidCode(5, ValidCode.CodeType.Alphas);
this.pictureBox2.Image = Bitmap.FromStream(validCode.CreateCheckCodeImage());
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希望本文所述对大家C#程序设计有所帮助。