应用ashx生成图形验证码实例教程【C#.Net教程】,ashx,验证,图形

这篇文章重要引见了asp.net运用ashx生成图形考证码的要领,连系实例情势剖析了asp.net生成图形考证码的步骤、完成要领与相干注意事项,须要的朋侪能够参考下

本文实例报告了asp.net运用ashx生成图形考证码的要领。分享给人人供人人参考，细致以下：

考证码的优点不必我多说，你们都懂的。我在网上看到有人把考证码直接写在aspx页面里，也就是说这类体式格局要求考证码即是要求一个页面，如许做很不科学。以下所示

<form id="form1" runat="server">
  <p>
    <asp:Image ID="Image1" runat="server" ImageUrl="Default.aspx" />
    <br />
    <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
    <asp:Button ID="Button1" runat="server" onclick="Button1_Click" Text="Button" />
  </p>
</form>

这个代码看着就以为写代码的人比较欠揍，代码写成如许子实在忧郁。考证吗也不写点script做下切换。

下面我引见一种体式格局来完成如许的功用

1. 写个ashx生成图形考证码

using System;
using System.Collections;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Services;
using System.Web.Services.Protocols;
using System.Xml.Linq;
using System.Web.SessionState;
using System.Drawing;
namespace usechecknum.ashx
{
  /// <summary>
  /// $codebehindclassname$ 的择要申明
  /// </summary>
  [WebService(Namespace = "http://tempuri.org/")]
  [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
  public class doCreateNum : IHttpHandler,IRequiresSessionState
  {
    public void ProcessRequest(HttpContext context)
    {
      context.Response.ContentType = "text/html";
      string checkCode = GetValidation(5); // 发生5位随机考证码字符
      context.Session["Code"] = checkCode; //将字符串保存到Session中，以便须要时举行考证
      System.Drawing.Bitmap image = new System.Drawing.Bitmap(70, 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);
        // 画图片的背景噪音线
        int i;
        for (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 System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold));
        System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2F, true);
        g.DrawString(checkCode, font, brush, 2, 2);
        //画图片的远景噪音点
        g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
        System.IO.MemoryStream ms = new System.IO.MemoryStream();
        image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
        context.Response.ClearContent();
        context.Response.ContentType = "image/Gif";
        context.Response.BinaryWrite(ms.ToArray());
      }
      finally
      {
        g.Dispose();
        image.Dispose();
      }
    }
    public string GetValidation(int num)
    {
      string str = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; //"或许写汉字也行"
      string validatecode = "";
      Random rd = new Random();
      for (int i = 0; i < num; i++)
      {
        validatecode += str.Substring(rd.Next(0, str.Length), 1);
      }
      return validatecode;
    }
    public bool IsReusable
    {
      get
      {
        return false;
      }
    }
  }
}

2. 在页面上显现考证码，由于我们生成的是图形，所以能够直接写在<img/>标签里，我们只要写段简朴的剧本就能够点击鼠标切换考证码了

<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="index.aspx.cs" Inherits="usechecknum._Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml" >
<head runat="server">
  <title>考证码的运用</title>
</head>
<script language="javascript" type="text/javascript">
  function changeCode() {
    var imgNode = document.getElementById("vimg");
    imgNode.src = "ashx/doCreateNum.ashx?t=" + (new Date()).valueOf(); // 这里加个时刻的参数是为了防备浏览器缓存的题目
  }
  </script>
<body>
  <form id="form1" runat="server">
   请输入考证码:<input type="text" name="checknum"/><img src="ashx/doCreateNum.ashx" id="vimg" onclick="changeCode()" />
  </form>
</body>
</html>

说了半天，该是时刻看看生成的考证码长什么样了