[转载]c#的验证码代码（能直接用）

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
using System.Drawing;

public partial class : System.Web.UI.Page//CheckCode是网页名字，另外，你要弄一个图片控件，将它的地址设为这个网页的名字。
{
// 验证码长度
private int codeLen = 4;
// 图片清晰度
private int fineness = 100;
// 图片宽度
private int imgWidth = 100;
// 图片高度
private int imgHeight = 24;
// 字体家族名称
private string fontFamily = "Arial Black";
// 字体大小
private int fontSize = 18;
// 字体样式
private int fontStyle = 0;
// 绘制起始坐标 X
private int posX = 0;
// 绘制起始坐标 Y
private int posY = 0;

//------------------------------------------------------------
// code.aspx 页面加载函数
//------------------------------------------------------------
private void Page_Load(object sender, System.EventArgs e)
{
#region 读取 Request 传递参数
// 获取代码长度设置
if (Request["CodeLen"] != null)
{
try
{
codeLen = Int32.Parse(Request["CodeLen"]);

// 规定验证码长度
if (codeLen < 4 || codeLen > 16)
throw new Exception("验证码长度必须在4到16之间");
}
catch (Exception Ex)
{
throw Ex;
}
}

// 获取图片清晰度设置
if (Request["Fineness"] != null)
{
try
{
fineness = Int32.Parse(Request["Fineness"]);

// 验证清晰度
if (fineness < 0 || fineness > 100)
throw new Exception("图片清晰度必须在0到100之间");
}
catch (Exception Ex)
{
throw Ex;
}
}

// 获取图片宽度
if (Request["ImgWidth"] != null)
{
try
{
imgWidth = Int32.Parse(Request["ImgWidth"]);

if (imgWidth < 16 || imgWidth > 480)
throw new Exception("图片宽度必须在16到480之间");
}
catch (Exception Ex)
{
throw Ex;
}
}

// 获取图片高度
if (Request["ImgHeight"] != null)
{
try
{
imgHeight = Int32.Parse(Request["ImgHeight"]);

if (imgHeight < 16 || imgHeight > 320)
throw new Exception("图片高度必须在16到320之间");
}
catch (Exception Ex)
{
throw Ex;
}
}

// 获取验证码字体家族名称
if (Request["FontFamily"] != null)
{
fontFamily = Request["FontFamily"];
}

// 获取验证码字体大小
if (Request["FontSize"] != null)
{
try
{
fontSize = Int32.Parse(Request["FontSize"]);

if (fontSize < 8 || fontSize > 72)
throw new Exception("字体大小必须在8到72之间");
}
catch (Exception Ex)
{
throw Ex;
}
}

// 获取字体样式
if (Request["FontStyle"] != null)
{
try
{
fontStyle = Int32.Parse(Request["FontStyle"]);
}
catch (Exception Ex)
{
throw Ex;
}
}

// 验证码绘制起始位置 X
if (Request["PosX"] != null)
{
try
{
posX = Int32.Parse(Request["PosX"]);
}
catch (Exception Ex)
{
throw Ex;
}
}

// 验证码绘制起始位置 Y
if (Request["PosY"] != null)
{
try
{
posY = Int32.Parse(Request["PosY"]);
}
catch (Exception Ex)
{
throw Ex;
}
}
#endregion

string code = Createcode();

// 生成BITMAP图像
Bitmap bitmap = new Bitmap(imgWidth, imgHeight);

// 给图像设置干扰
DisturbBitmap(bitmap);

// 绘制验证码图像
Drawcode(bitmap, code);

// 保存验证码图像，等待输出
bitmap.Save(Response.OutputStream, ImageFormat.Gif);
}

//------------------------------------------------------------
// 随机生成验证码，并保存到SESSION中
//------------------------------------------------------------
private string Createcode()
{
string code = "";

// 随机数对象
Random random = new Random();

for (int i = 0; i < codeLen; i++)
{
// 26: a - z
int n = random.Next(26);

// 将数字转换成大写字母
code += (char)(n + 65);
}

// 保存验证码
Session["code"] = code;

return code;
}

//------------------------------------------------------------
// 为图片设置干扰点
//------------------------------------------------------------
private void DisturbBitmap(Bitmap bitmap)
{
// 通过随机数生成
Random random = new Random();

for (int i = 0; i < bitmap.Width; i++)
{
for (int j = 0; j < bitmap.Height; j++)
{
if (random.Next(100) <= this.fineness)
bitmap.SetPixel(i, j, Color.White);
}
}

}

//------------------------------------------------------------
// 绘制验证码图片
//------------------------------------------------------------
private void Drawcode(Bitmap bitmap, string code)
{
// 获取绘制器对象
Graphics g = Graphics.FromImage(bitmap);

// 设置绘制字体
Font font = new Font(fontFamily, fontSize, GetFontStyle());
Pen myPen = new Pen(Color.Black,2);

//随机画两条线
Random r = new Random();
float x1 = r.Next(imgWidth);
float x2 = r.Next(imgWidth) ;
float y1 = r.Next(imgHeight);
float y2 = r.Next(imgHeight);
g.DrawLine(myPen, x1, y1, x2, y2);
x1 = r.Next(imgWidth );
x2 = r.Next(imgWidth);
y1 = r.Next(imgHeight);
y2 = r.Next(imgHeight);
g.DrawLine(myPen, x1, y1, x2, y2);
// 绘制验证码图像
g.DrawString(code, font, Brushes.Black, posX, posY);

}

//------------------------------------------------------------
// 换算验证码字体样式：1 粗体 2 斜体 3 粗斜体，默认为普通字体
//------------------------------------------------------------
private FontStyle GetFontStyle()
{
if (fontStyle == 1)
return FontStyle.Bold;
else if (fontStyle == 2)
return FontStyle.Italic;
else if (fontStyle == 3)
return FontStyle.Bold | FontStyle.Italic;
else
return FontStyle.Regular;