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
}
