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using System;
using System.Collections.Generic;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.IO;
using System.Drawing.Imaging;
namespace Dachie
{
public partial
class _Default : System.Web.UI.Page
{
protected void Page_Load(
object sender, EventArgs e)
{
//验证码长度
int CodeSize = 5;
//生成验证码值
string Code = CreateValidateNumber(CodeSize);
//创建验证码
CreateValidateGraphic(
this, Code);
}
/// <summary>
/// 得到验证码图片的长度
/// </summary>
/// <param name="validateNumLength">验证码的长度</param>
/// <returns></returns>
public static int GetImageWidth(
int validateNumLength)
{
return (
int)(validateNumLength * 12.5);
}
/// <summary>
/// 得到验证码的高度
/// </summary>
/// <returns></returns>
public static double GetImageHeight()
{
return 22.5;
}
/// <summary>
/// 验证码的最大长度
/// </summary>
public int MaxLength
{
get {
return 10; }
}
/// <summary>
/// 验证码的最小长度
/// </summary>
public int MinLength
{
get {
return 1; }
}
/// <summary>
/// 生成验证码
/// </summary>
/// <param name="length">指定验证码的长度</param>
/// <returns></returns>
public string CreateValidateNumber(
int length)
{
int[] randMembers =
new int[length];
int[] validateNums =
new int[length];
string validateNumberStr = "";
//生成起始序列值
int seekSeek =
unchecked((
int)DateTime.Now.Ticks);
Random seekRand =
new Random(seekSeek);
int beginSeek = (
int)seekRand.Next(0, Int32.MaxValue - length * 10000);
int[] seeks =
new int[length];
for (
int i = 0; i < length; i++)
{
beginSeek += 10000;
seeks[i] = beginSeek;
}
//生成随机数字
for (
int i = 0; i < length; i++)
{
Random rand =
new Random(seeks[i]);
int pownum = 1 * (
int)Math.Pow(10, length);
randMembers[i] = rand.Next(pownum, Int32.MaxValue);
}
//抽取随机数字
for (
int i = 0; i < length; i++)
{
string numStr = randMembers[i].ToString();
int numLength = numStr.Length;
Random rand =
new Random();
int numPosition = rand.Next(0, numLength - 1);
validateNums[i] = Int32.Parse(Math.Abs(Int64.Parse(numStr)).ToString().Substring(numPosition, 1));
}
//生成验证码
for (
int i = 0; i < length; i++)
{
validateNumberStr += validateNums[i].ToString();
}
return validateNumberStr;
}
/// <summary>
/// 创建验证码的图片
/// </summary>
/// <param name="containsPage">要输出到的page对象</param>
/// <param name="validateNum">验证码</param>
public void CreateValidateGraphic(Page containsPage,
string validateNum)
{
Bitmap image =
new Bitmap((
int)Math.Ceiling(validateNum.Length * 12.5), 22);
Graphics g = Graphics.FromImage(image);
try
{
//生成随机生成器
Random random =
new Random();
//清空图片背景色
g.Clear(Color.White);
//画图片的干扰线
for (
int i = 0; i < 25; 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.Silver), x1, y1, x2, y2);
}
Font font =
new Font("
Arial", 12, (FontStyle.Bold | FontStyle.Italic));
LinearGradientBrush brush =
new LinearGradientBrush(
new Rectangle(0, 0, image.Width, image.Height),
Color.Blue, Color.DarkRed, 1.2f,
true);
g.DrawString(validateNum, font, brush, 3, 2);
//画图片的前景干扰点
for (
int i = 0; i < 100; i++)
{
int x = random.Next(image.Width);
int y = random.Next(image.Height);
image.SetPixel(x, y, Color.FromArgb(random.Next()));
}
//画图片的边框线
g.DrawRectangle(
new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
//保存图片数据
MemoryStream stream =
new MemoryStream();
image.Save(stream, ImageFormat.Jpeg);
//输出图片
containsPage.Response.Clear();
containsPage.Response.ContentType = "
image/jpeg";
containsPage.Response.BinaryWrite(stream.ToArray());
}
finally
{
g.Dispose();
image.Dispose();
}
}
}
}