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asp.net 生成图片验证码

 2006-05-16 17:08:45 来源:WEB开发网   
核心提示:identifyingcode.aspx里没有内容略。identifyingcode.cs文件:using System;using System.Data;using System.Configuration;using System.Collections;using System.Web;using System

identifyingcode.aspx里没有内容略。
identifyingcode.cs文件:
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;
using System.Drawing.Imaging;
using System.IO;
public partial class identifyingcode : System.Web.UI.Page
{
   PRotected void Page_Load(object sender, EventArgs e)
   {
     string tmp = RndNum(4);
     HttpCookie a = new HttpCookie("ImageV", tmp);
     Response.Cookies.Add(a);
     this.ValidateCode(tmp);

   }
   private void ValidateCode(string VNum)
   {
     Bitmap Img = null;
     Graphics g = null;
     MemoryStream ms = null;

   int gheight = VNum.Length * 12;
     Img = new Bitmap(gheight, 25);
     g = Graphics.FromImage(Img);
     //背景颜色
     g.Clear(Color.LightSteelBlue);
     //文字字体
     Font f = new Font("Arial Black", 10);
     //文字颜色
     SolidBrush s = new SolidBrush(Color.RoyalBlue);
     g.DrawString(VNum, f, s, 3, 3);
     ms = new MemoryStream();
     Img.Save(ms, ImageFormat.Jpeg);
     Response.ClearContent();
     Response.ContentType = "images/Jpeg";
     Response.BinaryWrite(ms.ToArray());
     g.Dispose();
     Img.Dispose();
     Response.End();
   }

   private string RndNum(int VcodeNum)
   {
     string Vchar = "0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p" +
     ",q,r,s,t,u,v,w,x,y,z";
     string[] VcArray = Vchar.Split(new Char[] { ',' });
     string VNum = "";
     int temp = -1;

   Random rand = new Random();

   for (int i = 1; i < VcodeNum + 1; i++)
     {
       if (temp != -1)
       {
         rand = new Random(i * temp * unchecked((int)DateTime.Now.Ticks));
       }

     int t = rand.Next(35);
       if (temp != -1 && temp == t)
       {
         return RndNum(VcodeNum);
       }
       temp = t;
       VNum += VcArray[t];
     }
     return VNum;
   }

}
 
使用方法:
在需要它的页面html里添加
 <img src="identifyingcode.aspx" />
 

  HttpCookieCollection cookies = Request.Cookies;
  string tmp = cookies["ImageV"].Value;
  然后比tmp与获取的较验证码文本框中的值是否相同
 
出处:http://enuosky.cnblogs.com/archive/2006/05/15/400954.html

Tags:asp net 生成

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