最终效果：
项目目录：
Default.aspx前端代码：
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="Default" %> <!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> <script src="js/jquery-1.8.3.min.js"></script> <script type="text/javascript">
$(document).ready(function () {
$("#getimgcode").click(function () {
var imgSrc = $("#getcode");
var src = imgSrc.attr("src");
imgSrc.attr("src", chgUrl(src));
$("#info").html("");//同时清空提示信息。
}) //时间戳
//为了使每次生成图片不一致，即不让浏览器读缓存，所以需要加上时间戳
function chgUrl(url) {
var timestamp = (new Date()).valueOf();
url = url.substring(0, 15);
if ((url.indexOf("&") >= 0)) {
url = url + "×tamp=" + timestamp;
} else {
url = url + "?timestamp=" + timestamp;
}
return url;
} //检测验证码
//文本框内容变化事件
$('#myCode').bind('input propertychange', function () {
if ($(this).val().length >= 6) { //此处作用：实时的检测验证码是否正确。
//要求：但必须要当用户输入第4个字符时，才进行验证。
//原因：因为验证码是四位，所以输入第四个字符时验证，此处也可以用来验证账户名称等等。
var code = $("#myCode").attr("value");
code = "c=" + code;
$.ajax({
type: "POST",
url: "Verify.ashx",
data: code,
success: function (data) {
if (data == "0") {
$("#info").html("<b><i style = 'color:#FF0000'>Session为空！</i></b>");
}
if (data == "1") {
$("#info").html("<b><i style = 'color:#FF0000'>验证码填写错误！</i></b>");
}
if (data == "2") {
$("#info").html("<b><i style = 'color:#3AAC54'>验证码正确！</i></b>");
}
}
});
}
else {
$("#info").html("");//如果输入的字符不等于6位清空提示信息。
}
});
})
</script> </head>
<body>
<form id="form1" runat="server">
<div>
<table>
<tr>
<td>
验证码：
</td>
<td>
<input id="myCode" type="text" runat="server" size ="8"/>
</td>
<td>
<img id ="getcode" src="VerifyCode.aspx" width ="85" height ="25" style ="border:1px solid #d3d1d1;"/>
</td>
<td>
<a id="getimgcode" href="Javascript:void(0)" title ="点击刷验证码">看不清？</a>
</td>
<td>
<span id ="info"></span>
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
Default.aspx.cs后台代码：
原始生成，不做修改即可。
VerifyCode.aspx前台代码：
原始生成，不做修改即可。
VerifyCode.aspx.cs后台代码：
using System;
using System.Drawing;
using System.Web; public partial class VerifyCode : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
validatedCode v = new validatedCode();
string code = v.CreateVerifyCode(); //取随机码
v.CreateImageOnPage(code, this.Context); // 输出图片
Session["CheckCode"] = code; //创建Session
} public class validatedCode
{
#region 验证码长度(默认6个验证码的长度)
int length = 6;
public int Length
{
get
{
return length;
}
set
{
length = value;
}
}
#endregion #region 验证码字体大小(为了显示扭曲效果，默认40像素，可以自行修改)
int fontSize = 50;
public int FontSize
{
get
{
return fontSize;
}
set
{
fontSize = value;
}
}
#endregion #region 边框补(默认1像素)
int padding = 2;
public int Padding
{
get
{
return padding;
}
set
{
padding = value;
}
}
#endregion #region 是否输出燥点(默认不输出)
bool chaos = true;
public bool Chaos
{
get
{
return chaos;
}
set
{
chaos = value;
}
}
#endregion #region 输出燥点的颜色(默认灰色)
Color chaosColor = Color.LightGray;
public Color ChaosColor
{
get
{
return chaosColor;
}
set
{
chaosColor = value;
}
}
#endregion #region 自定义背景色(默认白色)
Color backgroundColor = Color.White;
public Color BackgroundColor
{
get
{
return backgroundColor;
}
set
{
backgroundColor = value;
}
}
#endregion #region 自定义随机颜色数组
Color[] colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
public Color[] Colors
{
get
{
return colors;
}
set
{
colors = value;
}
}
#endregion #region 自定义字体数组
string[] fonts = { "Arial", "Georgia" };
public string[] Fonts
{
get
{
return fonts;
}
set
{
fonts = value;
}
}
#endregion #region 自定义随机码字符串序列(使用逗号分隔)
string codeSerial = "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,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";
public string CodeSerial
{
get
{
return codeSerial;
}
set
{
codeSerial = value;
}
}
#endregion #region 产生波形滤镜效果 private const double PI = 3.1415926535897932384626433832795;
private const double PI2 = 6.283185307179586476925286766559; /// <summary>
/// 正弦曲线Wave扭曲图片（Edit By 51aspx.com）
/// </summary>
/// <param name="srcBmp">图片路径</param>
/// <param name="bXDir">如果扭曲则选择为True</param>
/// <param name="nMultValue">波形的幅度倍数，越大扭曲的程度越高，一般为3</param>
/// <param name="dPhase">波形的起始相位，取值区间[0-2*PI)</param>
/// <returns></returns>
public System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
{
System.Drawing.Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height); // 将位图背景填充为白色
System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(destBmp);
graph.FillRectangle(new SolidBrush(System.Drawing.Color.White), 0, 0, destBmp.Width, destBmp.Height);
graph.Dispose(); double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width; for (int i = 0; i < destBmp.Width; i++)
{
for (int j = 0; j < destBmp.Height; j++)
{
double dx = 0;
dx = bXDir ? (PI2 * (double)j) / dBaseAxisLen : (PI2 * (double)i) / dBaseAxisLen;
dx += dPhase;
double dy = Math.Sin(dx); // 取得当前点的颜色
int nOldX = 0, nOldY = 0;
nOldX = bXDir ? i + (int)(dy * dMultValue) : i;
nOldY = bXDir ? j : j + (int)(dy * dMultValue); System.Drawing.Color color = srcBmp.GetPixel(i, j);
if (nOldX >= 0 && nOldX < destBmp.Width
&& nOldY >= 0 && nOldY < destBmp.Height)
{
destBmp.SetPixel(nOldX, nOldY, color);
}
}
} return destBmp;
} #endregion #region 生成校验码图片
public Bitmap CreateImageCode(string code)
{
int fSize = FontSize;
int fWidth = fSize + Padding; int imageWidth = (int)(code.Length * fWidth) + 4 + Padding * 2;
int imageHeight = fSize * 2 + Padding; System.Drawing.Bitmap image = new System.Drawing.Bitmap(imageWidth, imageHeight); Graphics g = Graphics.FromImage(image); g.Clear(BackgroundColor); Random rand = new Random(); //给背景添加随机生成的燥点
if (this.Chaos)
{ Pen pen = new Pen(ChaosColor, 0);
int c = Length * 10; for (int i = 0; i < c; i++)
{
int x = rand.Next(image.Width);
int y = rand.Next(image.Height); g.DrawRectangle(pen, x, y, 1, 1);
}
} int left = 0, top = 0, top1 = 1, top2 = 1; int n1 = (imageHeight - FontSize - Padding * 2);
int n2 = n1 / 4;
top1 = n2;
top2 = n2 * 2; Font f;
Brush b; int cindex, findex; //随机字体和颜色的验证码字符
for (int i = 0; i < code.Length; i++)
{
cindex = rand.Next(Colors.Length - 1);
findex = rand.Next(Fonts.Length - 1); f = new System.Drawing.Font(Fonts[findex], fSize, System.Drawing.FontStyle.Bold);
b = new System.Drawing.SolidBrush(Colors[cindex]); if (i % 2 == 1)
{
top = top2;
}
else
{
top = top1;
} left = i * fWidth; g.DrawString(code.Substring(i, 1), f, b, left, top);
} //画一个边框 边框颜色为Color.Gainsboro
g.DrawRectangle(new Pen(Color.Gainsboro, 0), 0, 0, image.Width - 1, image.Height - 1);
g.Dispose(); //产生波形（Add By 51aspx.com）
image = TwistImage(image, true, 8, 4); return image;
}
#endregion #region 将创建好的图片输出到页面
public void CreateImageOnPage(string code, HttpContext context)
{
System.IO.MemoryStream ms = new System.IO.MemoryStream();
Bitmap image = this.CreateImageCode(code); image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg); context.Response.ClearContent();
context.Response.ContentType = "image/Jpeg";
context.Response.BinaryWrite(ms.GetBuffer()); ms.Close();
ms = null;
image.Dispose();
image = null;
}
#endregion #region 生成随机字符码
public string CreateVerifyCode(int codeLen)
{
if (codeLen == 0)
{
codeLen = Length;
} string[] arr = CodeSerial.Split(','); string code = ""; int randValue = -1; Random rand = new Random(unchecked((int)DateTime.Now.Ticks)); for (int i = 0; i < codeLen; i++)
{
randValue = rand.Next(0, arr.Length - 1); code += arr[randValue];
} return code;
}
public string CreateVerifyCode()
{
return CreateVerifyCode(0);
}
#endregion
}
}
Veify.ashx代码：
- 其中如果要在一般处理程序中能使用 Session 的话。
- 要 using System.Web.SessionState; 。
- 并继承 IRequiresSessionState 接口。
<%@ WebHandler Language="C#" Class="Handler" %> using System;
using System.Web;
using System.Web.SessionState; public class Handler : IHttpHandler, IRequiresSessionState { public void ProcessRequest (HttpContext context) {
context.Response.ContentType = "text/plain";
string VerifyCode = context.Request.Form["c"];
if (context.Session["CheckCode"] == null)
{
context.Response.Write("0");//session为空！
}
else
{
string Verifycode = context.Session["CheckCode"].ToString().ToUpper();
if (Verifycode != VerifyCode.ToUpper())
{
context.Response.Write("1");//验证码填写错误！
}
else
{
context.Response.Write("2");//验证码正确！
}
}
} public bool IsReusable {
get {
return false;
}
} }