创建一个页面，名称为VerificationCode.aspx
using System;
using System.Drawing;
using System.Drawing.Imaging;
namespace VerificationCodeDemo
{
public partial class VerificationCode : System.Web.UI.Page
{
/// <summary>
/// 页面初始化
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void Page_Load(object sender, EventArgs e)
{
string verificationCode = CreateRandomCode(4);
Session["VerificationCode"] = verificationCode;
CreateImage(verificationCode);
}
/// <summary>
/// 产生数字和字符混合的随机字符串
/// </summary>
/// <param name="i">随机字符的位数</param>
/// <returns>随机字符串</returns>
private string CreateRandomCode(int i)
{
string allChar = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
char[] allCharArray = allChar.ToCharArray();
string randomCode = string.Empty;
Random rand = new Random();
for (int j = 0; j < i; j++)
{
int k = rand.Next(61);
randomCode += allCharArray.GetValue(k);
}
return randomCode;
}
/// <summary>
/// 生成图象验证码
/// </summary>
/// <param name="verificationCode">随机字符串</param>
private void CreateImage(string verificationCode)
{
int iwidth = (int)(verificationCode.Length * 11.5);
Bitmap image = new Bitmap(iwidth, 20);
Graphics g = Graphics.FromImage(image);
Font f = new Font("Arial", 10, FontStyle.Bold);
Brush b = new SolidBrush(Color.Azure); // 字母白色
g.Clear(Color.Brown); // 背景灰色
g.DrawString(verificationCode, f, b, 3, 3);
Pen blackPen = new Pen(Color.Black, 0);
Random rand = new Random();
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, ImageFormat.Jpeg);
Response.ClearContent();
Response.ContentType = "image/Jpeg";
Response.BinaryWrite(ms.ToArray());
g.Dispose();
image.Dispose();
}
}
using System.Drawing;
using System.Drawing.Imaging;
namespace VerificationCodeDemo
{
public partial class VerificationCode : System.Web.UI.Page
{
/// <summary>
/// 页面初始化
/// </summary>
/// <param name="sender"></param>
/// <param name="e"></param>
protected void Page_Load(object sender, EventArgs e)
{
string verificationCode = CreateRandomCode(4);
Session["VerificationCode"] = verificationCode;
CreateImage(verificationCode);
}
/// <summary>
/// 产生数字和字符混合的随机字符串
/// </summary>
/// <param name="i">随机字符的位数</param>
/// <returns>随机字符串</returns>
private string CreateRandomCode(int i)
{
string allChar = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
char[] allCharArray = allChar.ToCharArray();
string randomCode = string.Empty;
Random rand = new Random();
for (int j = 0; j < i; j++)
{
int k = rand.Next(61);
randomCode += allCharArray.GetValue(k);
}
return randomCode;
}
/// <summary>
/// 生成图象验证码
/// </summary>
/// <param name="verificationCode">随机字符串</param>
private void CreateImage(string verificationCode)
{
int iwidth = (int)(verificationCode.Length * 11.5);
Bitmap image = new Bitmap(iwidth, 20);
Graphics g = Graphics.FromImage(image);
Font f = new Font("Arial", 10, FontStyle.Bold);
Brush b = new SolidBrush(Color.Azure); // 字母白色
g.Clear(Color.Brown); // 背景灰色
g.DrawString(verificationCode, f, b, 3, 3);
Pen blackPen = new Pen(Color.Black, 0);
Random rand = new Random();
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, ImageFormat.Jpeg);
Response.ClearContent();
Response.ContentType = "image/Jpeg";
Response.BinaryWrite(ms.ToArray());
g.Dispose();
image.Dispose();
}
}
}
再创建一个页面，名称为WebForm1.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="WebForm1.aspx.cs" Inherits="VerificationCodeDemo.WebForm1" %>
<!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>验证码例子</title>
<script language="javascript" type="text/javascript">
function check() {
var v = document.getElementById("image1");
v.setAttribute('src', 'VerificationCode.aspx?' + Math.random());
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<!-- 直接点击图片或文字均刷新 -->
<img id="image1" src="VerificationCode.aspx" alt="验证码" onclick="this.src=this.src+'?'" />
<a href="javascript:check()">看不清楚</a>
</div>
</form>
</body>
<!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>验证码例子</title>
<script language="javascript" type="text/javascript">
function check() {
var v = document.getElementById("image1");
v.setAttribute('src', 'VerificationCode.aspx?' + Math.random());
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<!-- 直接点击图片或文字均刷新 -->
<img id="image1" src="VerificationCode.aspx" alt="验证码" onclick="this.src=this.src+'?'" />
<a href="javascript:check()">看不清楚</a>
</div>
</form>
</body>
</html>