using System;
using System.Data;
using System.Web;
using System.Drawing;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing.Drawing2D;
using System.Threading;
/*
* 版权：C/S框架网 www.csframework.com
*
* 生成图片验证码业务逻辑
*/
namespace CSFramework.BLL
{
   /// <summary>
   /// 生成图片验证码
   /// </summary>
   public class CGenValidateCode
   {
      #region 随机字符验证码
      
      private Page _page = null;
      public CGenValidateCode(Page page)
      {
         _page = page;
      }
      
      /// <summary>
      /// 产生验证码
      /// </summary>
      /// <returns></returns>
      private string CreateCode(int codeLength)
      {
         //去除字母与数字相近的数字或字母
         string chars = "2,3,5,6,7,8,9,A,B,C,D,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,U,V,W,X,Y,Z,"
         "a,b,c,d,e,f,g,h,i,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z";
         
         string[] strArr = chars.Split(',');
         string code = "";
         Random rand = new Random();
         for (int i = 0; i < codeLength; i )
         {
            code = strArr[rand.Next(0, strArr.Length)];
            Thread.Sleep(5);
         }
         return code;
      }
      
      /// <summary>
      /// 输出验证图片
      /// </summary>
      /// <param name="code"></param>
      private void CreateImage(string code)
      {
         Bitmap image = new Bitmap(75, 25); //验证码图片模块
         Graphics g = Graphics.FromImage(image);
         WebColorConverter ww = new WebColorConverter();
         g.Clear((Color)ww.ConvertFromString("White")); //底色
         
         Random random = new Random();
         
         //画图片的背景噪音线
         for (int i = 0; i < 6; i )
         {
            int x1 = random.Next(image.Width);
            Thread.Sleep(5);
            int x2 = random.Next(image.Width);
            int y1 = random.Next(image.Height);
            Thread.Sleep(5);
            int y2 = random.Next(image.Height);
            
            g.DrawLine(new Pen(Color.Blue), x1, y1, x2, y2);
         }
         
         //验证码字体
         Font font = new Font("arial", 14, FontStyle.Bold | FontStyle.Italic);
         
         //画笔对象
         LinearGradientBrush brush = new LinearGradientBrush(
         new Rectangle(0, 0, image.Width, image.Height), Color.Red, Color.Gray, 1.2f, true);
         g.DrawString(code, font, brush, 0, 0);
         
         //画图片的边框线
         g.DrawRectangle(new Pen(Color.Gray), 0, 0, image.Width - 1, image.Height - 1);
         
         System.IO.MemoryStream ms = new System.IO.MemoryStream();
         image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
         _page.Response.ClearContent();
         _page.Response.ContentType = "image/jpeg"; //HTTP MIME TYPE 设为图片输出
         _page.Response.BinaryWrite(ms.ToArray());
         g.Dispose();
         image.Dispose();
      }
      
      /// <summary>
      /// 生成新的验证码
      /// </summary>
      public void Generate()
      {
         string checkCode = this.CreateCode(5); //生成新的验证码
         _page.Session["csframework_code"] = checkCode;
         this.CreateImage(checkCode);
      }
      
      /// <summary>
      /// 检验用户输入的验证码
      /// </summary>
      /// <param name="validatePage">要验证的页面</param>
      /// <param name="input">用户输入的验证码</param>
      /// <returns></returns>
      public static bool ValidateLastCode(Page validatePage, string input)
      {
         //将对象转换为字符串
         string lastCode = Convert.ToString(validatePage.Session["csframework_code"]);
         return (input.ToUpper() == lastCode.ToUpper());
      }
      
      #endregion
   }
   
}


// 来源:www.CSFramework.com, C/S结构框架学习网

<td class="td2">

   <span style="color: Gray;">(不区分大小写)</span>

   <a href="#" onclick="document.getElementById('vcode').src='http://www.csframework.com/do-gen-code.aspx?temp='+ (new Date().getTime().toString(36));return false;">重新生成</a>

</td>