using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Web.UI;
using System.Drawing.Drawing2D;
using System.IO;namespace SeniOA.MVC
{/// <summary>/// 生成验证码的类/// </summary>public class ValidateCode{public ValidateCode(){}/// <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 CreateValidateCode(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(numStr.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(string validateCode){Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 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(validateCode, 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);//输出图片流
                containsPage.Response.Clear();containsPage.Response.ContentType = "image/jpeg";containsPage.Response.BinaryWrite(stream.ToArray());}finally{g.Dispose();image.Dispose();}}/// <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 * 12.0);}/// <summary>/// 得到验证码的高度/// </summary>/// <returns></returns>public static double GetImageHeight(){return 22.5;}}
}

/// <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 byte[] CreateValidateGraphic(string validateCode)
{Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 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(validateCode, 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);//输出图片流return stream.ToArray();}finally{g.Dispose();image.Dispose();}
}

public ActionResult GetValidateCode()
{ValidateCode vCode = new ValidateCode();string code = vCode.CreateValidateCode(5);Session["ValidateCode"] = code;byte[] bytes = vCode.CreateValidateGraphic(code);return File(bytes, @"image/jpeg");
}

[AcceptVerbs(HttpVerbs.Post)]
public ActionResult Login(string userName, string password, bool rememberMe, string returnUrl,string code)
{if (Session["ValidateCode"].ToString() != code){ModelState.AddModelError("code", "validate code is error");return View();}//此处验证用户名、密码if (!ValidateLogOn(userName, password)){return View();}//验证成功
    FormsAuthentication.SetAuthCookie(userName, rememberMe);if (!String.IsNullOrEmpty(returnUrl)){return Redirect(returnUrl);}else{return RedirectToAction("Index", "Home");}
}

<script type="text/javascript" src="http://www.cnblogs.com/Scripts/jquery-1.3.2-vsdoc.js"></script>
<script type="text/javascript">$(function() {$("#valiCode").bind("click", function() {this.src = "../Account/GetValidateCode?time=" + (new Date()).getTime();});//alert("good");
    });
</script>