.Net 点击实现验证码的刷新(转载)
验证码是由4个随机数和一些使用GDI+技术绘制的噪点而组成的。
验证码生成文件:CheckCode.aspx.cs
如果要在验证码中同时有字母和数字,可以将生成验证码的方法改为:
在页面中调用:
验证码生成文件:CheckCode.aspx.cs
Code
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;
using System.Drawing;
public partial class Login_CheckCode : 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());
}
/**//// <summary>
/// 生成验证码图片
/// </summary>
private void CreateCheckCodeImage(string checkCode)
{
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 < 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 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();
}
}
/**//// <summary>
/// 生成验证码
/// </summary>
private string GenerateCheckCode()
{
int number;
char code;
string checkCode = string.Empty;
Random random = new Random();
for (int i = 0; i < 4; i++)
{
number = random.Next(10);
code = (char)('0' + (char)number);
checkCode += code.ToString();
}
//将生成的随机验证码添加到Cookies中
Response.Cookies.Add(new HttpCookie("CheckCode",checkCode));
return checkCode;
}
}
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;
using System.Drawing;
public partial class Login_CheckCode : 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());
}
/**//// <summary>
/// 生成验证码图片
/// </summary>
private void CreateCheckCodeImage(string checkCode)
{
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 < 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 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();
}
}
/**//// <summary>
/// 生成验证码
/// </summary>
private string GenerateCheckCode()
{
int number;
char code;
string checkCode = string.Empty;
Random random = new Random();
for (int i = 0; i < 4; i++)
{
number = random.Next(10);
code = (char)('0' + (char)number);
checkCode += code.ToString();
}
//将生成的随机验证码添加到Cookies中
Response.Cookies.Add(new HttpCookie("CheckCode",checkCode));
return checkCode;
}
}
如果要在验证码中同时有字母和数字,可以将生成验证码的方法改为:
Code
private string GenerateCheckCode()()
{
char[] s = new char[]{'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'};
string num = "";
Random r = new Random();
for (int i = 0; i < 4; i++)
{
num += s[r.Next(0, s.Length)].ToString();
}
return num;
}
private string GenerateCheckCode()()
{
char[] s = new char[]{'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'};
string num = "";
Random r = new Random();
for (int i = 0; i < 4; i++)
{
num += s[r.Next(0, s.Length)].ToString();
}
return num;
}
在页面中调用:
<img src="CheckCode.aspx" alt="看不清,请点击我!" id="imgCheckCode" onclick="this.src='CheckCode.aspx?abc='+Math.random()"/>
注意:有一点要说明,当点击刷新时,validate.asp?后面一定要有一个参数,若没有这个无效的参数,程序会认为你请求的是同一个文件,因而不会刷新的。这里的参数abc是个随意的,只起改变请求文件的作用。