ValidateCode.ashx
<%@ WebHandler Language="C#" class="ValidateCode" %>
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.Drawing.Drawing2D;
using System.Drawing;
public class ValidateCode : IHttpHandler
{
public void ProcessRequest(HttpContext context)
{
context.Response.Cache.SetCacheability(HttpCacheability.NoCache);
this.CreateCheckCodeImage(GenerateCheckCode(context), context);
}
public bool IsReusable
{
get
{
return false;
}
}
private string GenerateCheckCode(HttpContext context)
{
int number;
char code;
string checkCode = String.Empty;
System.Random random = new Random();
for (int i = 0; i < 6; i++)
{
number = random.Next();
if (number % 2 == 0)
code = (char)(‘0‘ + (char)(number % 10));
else if (number % 3 == 0)
code = (char)(‘A‘ + (char)(number % 26));
else
code = (char)(‘a‘ + (char)(number % 26));
checkCode += code.ToString();
}
context.Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));
//也可以存到Seesion里．
//context.Session["CheckCode"] = checkCode;
return checkCode;
}
private void CreateCheckCodeImage(string checkCode, HttpContext context)
{
if (checkCode == null || checkCode.Trim() == String.Empty)
return;
Bitmap image = new Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 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
for (int 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.FontStyle.Italic));
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);
//画图片的前景噪音点
for (int i = 0; i < 100; i++)
{
int x = random.Next(image.Width);
int y = random.Next(image.Height);
image.SetPixel(x, y, Color.FromArgb(random.Next()));
}
//画图片的边框线
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();
}
}
}
}
页面:
<img src="ValidateCode.ashx" title="看不清？点击刷新" style="cursor:pointer" onclick="this.src=‘ValidateCode.ashx?_=‘+Math.random()">
后台代码:
using System; using System.Data; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls;
public partial class Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
if (Request.Cookies["CheckCode"] == null)
{
lblMessage.Text = "您的浏览器设置已被禁用 Cookies，您必须设置浏览器允许使用 Cookies 选项后才能使用本系统。";
lblMessage.Visible = true;
return;
}
if (String.Compare(Request.Cookies["CheckCode"].Value, txtCheckCode.Text, true) != 0)
{
lblMessage.Text = "验证码错误，请输入正确的验证码。";
lblMessage.Visible = true;
return;
}
//在这执行下一步
//CheckCode是存到Session里的
//if (Session["CheckCode"] != null) //{ // if (String.Compare(Session["CheckCode"].ToString(), txtCheckCode.Text.Trim(), true) != 0) // { // lblMessage.Text = "验证码错误，请输入正确的验证码。"; // lblMessage.Visible = true; // return; // } // else // {//在这执行下一步 // } //} } }