asp.net登录验证码实现方法
前端添加的标签和方法：
验证码： 代码如下:<input id="txtVerifyCode" type="text" maxlength="5" style="line-height: 30px; height: 30px; width: 80px;border:solid 1px #d4d4d4;" class="input"/> <img src="" alt="点击刷新" id="imgValidateCode" style="width: 100px; height: 30px; line-height: 30px; vertical-align: middle;" />  点击图片刷新</p>//标签
$(function () {
$("#imgValidateCode").click(function () {
DoFresh();
});
DoFresh();
})
function DoFresh() {
var img = $("#imgValidateCode");
img.attr("src", "VerifyCode.aspx?random=" + Math.random());
} //添加的方法，src是生成图片的aspx的地址
然后在项目中在新建一个VerifyCode.aspx，下面是aspx的代码：
<%@ Page Language="C#" AutoEventWireup="true" CodeBehind="VerifyCode.aspx.cs" Inherits="Form.VerifyCode" %>
<!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 id="Head1" runat="server">
<title></title>
</head>
<body>
<form id="form1" runat="server">
<div>
</div>
</form>
</body>
</html>
接着是aspx.cs的代码：
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Drawing;
namespace Form
{
public partial class VerifyCode : System.Web.UI.Page
{
public static string HZ;
/// <summary>
/// 验证码的最大长度
/// </summary>
public int MaxLength
{
get { return 10; }
}
/// <summary>
/// 验证码的最小长度
/// </summary>
public int MinLength
{
get { return 1; }
}
protected void Page_Load(object sender, EventArgs e)
{
string[] str = CreateValidateNumber(4);
string strcode = string.Empty;
for (int i = 0; i < str.Length; i++)
{
strcode += str[i];
}
CreateCheckCodeImage(str);
HZ = strcode;
Response.Write(HZ);
//验证码存入session
Session["ValidateCode"] = HZ;
}
/// <summary>
/// 生成验证码
/// </summary>
/// <param name="length">指定验证码的长度</param>
/// <returns>验证码</returns>
public string[] CreateValidateNumber(int length)
{
string Vchar = "1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,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,P,Q" +
",R,S,T,U,V,W,X,Y,Z";
string[] VcArray = Vchar.Split(new Char[] { ',' });//拆分成数组
string[] num = new string[length];
int temp = -1;//记录上次随机数值，尽量避避免生产几个一样的随机数
Random rand = new Random();
//采用一个简单的算法以保证生成随机数的不同
for (int i = 1; i < length + 1; i++)
{
if (temp != -1)
{
rand = new Random(i * temp * unchecked((int)DateTime.Now.Ticks));
}
int t = rand.Next(VcArray.Length-1);
if (temp != -1 && temp == t)
{
return CreateValidateNumber(length);
}
temp = t;
num[i - 1] = VcArray[t];
//num.SetValue(VcArray[t]);
//VNum += VcArray[t];
}
return num;
}
private void CreateCheckCodeImage(string[] checkCode)
{
if (checkCode == null || checkCode.Length <= 0)
return;
System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 32.5)), 60);
System.Drawing.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);
//定义颜色
Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
//画图片的背景噪音线
for (int i = 0; i < 25; i++)
{
int cindex = random.Next(7);
int findex = random.Next(5);
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(c[cindex]), x1, y1, x2, y2);
}
//定义字体
string[] f = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };
for (int k = 0; k <= checkCode.Length - 1; k++)
{
int cindex = random.Next(7);
int findex = random.Next(5);
Font drawFont = new Font(f[findex], 26, (System.Drawing.FontStyle.Bold));
SolidBrush drawBrush = new SolidBrush(c[cindex]);
float x = 5.0F;
float y = 0.0F;
float width = 42.0F;
float height = 48.0F;
int sjx = random.Next(10);
int sjy = random.Next(image.Height - (int)height);
RectangleF drawRect = new RectangleF(x + sjx + (k * 25), y + sjy, width, height);
StringFormat drawFormat = new StringFormat();
drawFormat.Alignment = StringAlignment.Center;
g.DrawString(checkCode[k], drawFont, drawBrush, drawRect, drawFormat);
}
//画图片的前景噪音点
for (int i = 0; i < 500; i++)
{
int x = random.Next(image.Width);
int y = random.Next(image.Height);
image.SetPixel(x, y, Color.FromArgb(random.Next()));
}
int cindex1 = random.Next(7);
//画图片的边框线
g.DrawRectangle(new Pen(c[cindex1]), 0, 0, image.Width - 1, image.Height - 1);
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();
}
}
}
}
于是！就可以生成验证码了，然后自己再把编写验证版的判断逻辑写好就可以啦！
