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图片验证码

1、创建一个网站,只使用后台生成验证码,并输出图片流跟图片验证码的字符

using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;using System.Drawing;public partial class YZM : System.Web.UI.Page{    protected void Page_Load(object sender, EventArgs e)    {        //一、引用using System.Drawing;类        //二、准备画布        Bitmap img = new Bitmap(60,30);        //三、往图片上画验证码        //1、准备绘制类,相当于铺好画布准备绘画        Graphics g = Graphics.FromImage(img);        //2、准备绘画的内容与工具        string all = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ1234567890";//验证内容        Random r = new Random();//实例化随机类        string aa = "";        for(int i=0;i<4;i++)        {            aa += all.Substring(r.Next(all.Length), 1);//随机截取字符组成验证码        }        Session["YZM"] = aa;//验证的数据用session传过去        Font f = new Font("微软雅黑",16);//字体格式        SolidBrush b = new SolidBrush(Color.Green);//准备画刷        //3、绘制验证码        g.DrawString(aa, f, b, 0, 0);        //四、输出验证码到页面上        img.Save(Response.OutputStream,System.Drawing.Imaging.ImageFormat.Png);//数据流,输出格式            }}

2、图片验证码需要验证的界面

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="PMShtml.aspx.cs" Inherits="PMShtml" %><!DOCTYPE html><html xmlns="http://www.w3.org/1999/xhtml"><head runat="server"><meta http-equiv="Content-Type" content="text/html; charset=utf-8"/>    <title></title></head><body>    <form id="form1" runat="server">    <div>        <asp:TextBox ID="TextBox1" runat="server"></asp:TextBox><asp:Image ID="Image1" runat="server" ImageUrl="~/YZM.aspx" /><br />        <asp:Button ID="Button1" runat="server" Text="验证" /><asp:Label ID="Label1" runat="server" Text="" ForeColor="Red"></asp:Label>    </div>    </form></body></html><script type="text/javascript">    //验证图片的点击事件,点击图片重新换一张图片    var bb = 0;    document.getElementById("Image1").onclick = function () {        this.setAttribute("src", "yzm.aspx?aa=" + bb );        bb++;    }</script>

界面后台

using System;using System.Collections.Generic;using System.Linq;using System.Web;using System.Web.UI;using System.Web.UI.WebControls;public partial class PMShtml : System.Web.UI.Page{    protected void Page_Load(object sender, EventArgs e)    {        Button1.Click += Button1_Click;//验证按钮事件    }    //验证按钮开始    void Button1_Click(object sender, EventArgs e)    {        if (Session["YZM"] != null)        {            if (TextBox1.Text == Session["YZM"].ToString())            {                Label1.Text = "验证成功!";            }            else            {                Label1.Text = "验证失败!";            }        }    }    //验证按钮结束}

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图片验证码