本文介绍的ASP.NET生成验证码代码，来源于eping的博客，挺简单，内容细节都说得很清楚，实现方法下文
using System;
using System.Data;
using System.Configuration;
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;
using System.Drawing; //添加引用
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//调用自定义方法绘制验证码
CreateCheckCodeImage(GenerateCheckCode());
}
private string GenerateCheckCode()
{
//创建整型型变量
int number;
//创建字符型变量
char code;
//创建字符串变量并初始化为空
string checkCode = String.Empty;
//创建Random对象
Random random = new Random();
//使用For循环生成4个数字
for (int i = 0; i < 4; i++)
{
//生成一个随机数
number = random.Next();
//将数字转换成为字符型
code = (char)('0' + (char)(number % 10));
checkCode += code.ToString();
}
//将生成的随机数添加到Cookies中
Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));
//返回字符串
return checkCode;
}
private void CreateCheckCodeImage(string checkCode)
{
//判断字符串不等于空和null
if (checkCode == null || checkCode.Trim() == String.Empty)
return;
//创建一个位图对象
System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
//创建Graphics对象
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 < 2; 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.Black), x1, y1, x2, y2);
}
Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold));
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);
//将图片输出到页面上
System.IO.MemoryStream ms = new System.IO.MemoryStream();
image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
Response.ClearContent();
Response.ContentType = "image/Gif";
Response.BinaryWrite(ms.ToArray());
}
finally
{
g.Dispose();
image.Dispose();
}
}
}
<img id="imgCode" alt="看不清，请点击我！" src="CheckCode.aspx"
style="cursor: hand; width: 76px; height: 21px" onclick="this.src=this.src+'?'" />
