C#验证码

using

System;

using

System.Drawing;

using

System.Drawing.Drawing2D;

using

System.Drawing.Imaging;

using

System.IO;

using

System.Text;

using

System.Web;

namespace

Demo

{

/// <summary>

/// Captcha

/// </summary>

public

class

Captcha

{

#region Private Field

/// <summary>

/// 随机种子

/// </summary>

private

Random objRandom =

new

Random();

#endregion

#region Public Property

#region 验证码长度

/// <summary>

/// 验证码长度

/// </summary>

private

int

length = 4;

/// <summary>

/// 验证码长度(默认为4)

/// </summary>

public

int

Length

{

get

{

return

this

.length; }

set

{

this

.length = value; }

}

#endregion

#region 验证码字符串

/// <summary>

/// 验证码字符串

/// </summary>

private

string

verifyCodeText =

null

;

/// <summary>

/// 验证码字符串

/// </summary>

public

string

VerifyCodeText

{

get

{

return

this

.verifyCodeText; }

set

{

this

.verifyCodeText =value; }

}

#endregion

#region 是否加入小写字母

/// <summary>

/// 是否加入小写字母

/// </summary>

private

bool

addLowerLetter =

false

;

/// <summary>

/// 是否加入小写字母(不包括o)

/// </summary>

public

bool

AddLowerLetter

{

get

{

return

this

.addLowerLetter; }

set

{

this

.addLowerLetter =value; }

}

#endregion

#region 是否加入大写字母

/// <summary>

/// 是否加入大写字母

/// </summary>

private

bool

addUpperLetter =

false

;

/// <summary>

/// 是否加入大写字母(不包括O)

/// </summary>

public

bool

AddUpperLetter

{

get

{

return

this

.addUpperLetter; }

set

{

this

.addUpperLetter =value; }

}

#endregion

#region 字体大小

/// <summary>

/// 字体大小

/// </summary>

private

int

fontSize = 18;

/// <summary>

/// 字体大小(默认为18)

/// </summary>

public

int

FontSize

{

get

{

return

this

.fontSize; }

set

{

this

.fontSize = value; }

}

#endregion

#region 字体颜色

/// <summary>

/// 字体颜色

/// </summary>

private

Color fontColor = Color.Blue;

/// <summary>

/// 字体颜色(默认为Blue)

/// </summary>

public

Color FontColor

{

get

{

return

this

.fontColor; }

set

{

this

.fontColor = value; }

}

#endregion

#region 字体类型

/// <summary>

/// 字体类型

/// </summary>

private

string

fontFamily =

"Verdana"

;

/// <summary>

/// 字体类型(默认为Verdana)

/// </summary>

public

string

FontFamily

{

get

{

return

this

.fontFamily; }

set

{

this

.fontFamily =value; }

}

#endregion

#region 背景色

/// <summary>

/// 背景色

/// </summary>

private

Color backgroundColor = Color.AliceBlue;

/// <summary>

/// 背景色(默认为AliceBlue)

/// </summary>

public

Color BackgroundColor

{

get

{

return

this

.backgroundColor; }

set

{

this

.backgroundColor = value; }

}

#endregion

#region 前景噪点数量

/// <summary>

/// 前景噪点数量

/// </summary>

private

int

foreNoisePointCount = 2;

/// <summary>

/// 前景噪点数量(默认为2)

/// </summary>

public

int

ForeNoisePointCount

{

get

{

return

this

.foreNoisePointCount; }

set

{

this

.foreNoisePointCount = value; }

}

#endregion

#region 随机码的旋转角度

/// <summary>

/// 随机码的旋转角度

/// </summary>

private

int

randomAngle = 45;

/// <summary>

/// 随机码的旋转角度(默认为40度)

/// </summary>

public

int

RandomAngle

{

get

{

return

this

.randomAngle; }

set

{

this

.randomAngle = value; }

}

#endregion

#endregion

#region Constructor Method

/// <summary>

/// 构造方法

/// </summary>

public

Captcha()

{

this

.GetText();

}

#endregion

#region Private Method

/// <summary>

/// 得到验证码字符串

/// </summary>

private

void

GetText()

{

//没有外部输入验证码时随机生成

if

(String.IsNullOrEmpty(

this

.verifyCodeText))

{

StringBuilder objStringBuilder =

new

StringBuilder();

//加入数字1-9

for

(

int

i = 1; i <= 9; i++)

{

objStringBuilder.Append(i.ToString());

}

//加入大写字母A-Z，不包括O

if

(

this

.addUpperLetter)

{

char

temp =

' '

;

for

(

int

i = 0; i < 26; i++)

{

temp =Convert.ToChar(i + 65);

//如果生成的字母不是'O'

if

(!temp.Equals(

'O'

))

{

objStringBuilder.Append(temp);

}

}

}

//加入小写字母a-z，不包括o

if

(

this

.addLowerLetter)

{

char

temp =

' '

;

for

(

int

i = 0; i < 26; i++)

{

temp =Convert.ToChar(i + 97);

//如果生成的字母不是'o'

if

(!temp.Equals(

'o'

))

{

objStringBuilder.Append(temp);

}

}

}

//生成验证码字符串

{

int

index = 0;

for

(

int

i = 0; i < length; i++)

{

index = objRandom.Next(0, objStringBuilder.Length);

this

.verifyCodeText += objStringBuilder[index];

objStringBuilder.Remove(index, 1);

}

}

}

}

/// <summary>

/// 得到验证码图片

/// </summary>

private

Bitmap GetImage()

{

Bitmap result =

null

;

//创建绘图

result =

new

Bitmap(

this

.verifyCodeText.Length * 16, 25);

using

(Graphics objGraphics = Graphics.FromImage(result))

{

objGraphics.SmoothingMode = SmoothingMode.HighQuality;

//清除整个绘图面并以指定背景色填充

objGraphics.Clear(

this

.backgroundColor);

//创建画笔

using

(SolidBrush objSolidBrush =

new

SolidBrush(

this

.fontColor))

{

this

.AddForeNoisePoint(result);

this

.AddBackgroundNoisePoint(result, objGraphics);

//文字居中

StringFormat objStringFormat =

new

StringFormat(StringFormatFlags.NoClip);

objStringFormat.Alignment = StringAlignment.Center;

objStringFormat.LineAlignment = StringAlignment.Center;

//字体样式

Font objFont =

new

Font(

this

.fontFamily, objRandom.Next(

this

.fontSize - 3,

this

.fontSize), FontStyle.Regular);

//验证码旋转，防止机器识别

char

[] chars =

this

.verifyCodeText.ToCharArray();

for

(

int

i = 0; i < chars.Length; i++)

{

//转动的度数

float

angle = objRandom.Next(-

this

.randomAngle,

this

.randomAngle);

objGraphics.TranslateTransform(12, 12);

objGraphics.RotateTransform(angle);

objGraphics.DrawString(chars[i].ToString(), objFont, objSolidBrush, -2, 2, objStringFormat);

objGraphics.RotateTransform(-angle);

objGraphics.TranslateTransform(2, -12);

}

}

}

return

result;

}

/// <summary>

/// 添加前景噪点

/// </summary>

/// <param name="objBitmap"></param>

private

void

AddForeNoisePoint(Bitmap objBitmap)

{

for

(

int

i = 0; i < objBitmap.Width *

this

.foreNoisePointCount; i++)

{

objBitmap.SetPixel(objRandom.Next(objBitmap.Width), objRandom.Next(objBitmap.Height),

this

.fontColor);

}

}

/// <summary>

/// 添加背景噪点

/// </summary>

/// <param name="objBitmap"></param>

/// <param name="objGraphics"></param>

private

void

AddBackgroundNoisePoint(Bitmap objBitmap, Graphics objGraphics)

{

using

(Pen objPen =

new

Pen(Color.Azure, 0))

{

for

(

int

i = 0; i < objBitmap.Width *2; i++)

{

objGraphics.DrawRectangle(objPen, objRandom.Next(objBitmap.Width), objRandom.Next(objBitmap.Height), 1, 1);

}

}

}

#endregion

#region Public Method

public

void

Output(HttpResponse objHttpResponse)

{

using

(Bitmap objBitmap =

this

.GetImage())

{

if

(objBitmap !=

null

)

{

using

(MemoryStream objMS =

new

MemoryStream())

{

objBitmap.Save(objMS, ImageFormat.Jpeg);

HttpContext.Current.Response.ClearContent();

HttpContext.Current.Response.ContentType =

"image/Jpeg"

;

HttpContext.Current.Response.BinaryWrite(objMS.ToArray());

HttpContext.Current.Response.Flush();

HttpContext.Current.Response.End();

}

}

}

}

#endregion

}

}