完整asp.net图形验证码程序
1、测试页面：Default.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!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 runat="server">
<title>ASP.NET验证码</title>
</head>
<body>
<form id="form1" runat="server">
<div>
请输入验证码：<input id="txtVI" type="text" name="view_id" runat="server" maxlength="5" size="5"/>
<asp:Image id="Image1" runat="server" ImageUrl="ValidateCode.aspx" ImageAlign="Middle" />
<asp:RequiredFieldValidator ID="RequiredFieldValidator1" runat="server" ErrorMessage="您没有输入验证码" ControlToValidate="txtVI"></asp:RequiredFieldValidator><br />
<asp:Button ID="Button1" runat="server" Text="提 交" OnClick="Button1_Click" /></div>
</form>
</body>
</html>
2、测试页面后台：Default.aspx.cs
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;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void Button1_Click(object sender, EventArgs e)
{
string VNum;
VNum = Session["VNum"].ToString();
Session.Abandon();
ViewState["VNum"] = VNum;
if (txtVI.Value == ViewState["VNum"].ToString())
{
Response.Write("<script>alert('验证码输入正确！');</script>");
return;
}
else
{
// VIWShow.Text="所填写的验证码不正确！";
Response.Write("<script>alert('验证码输入错误！');</script>");
return;
}
}
}
3、生成验证码页面:ValidateCode.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="ValidateCode.aspx.cs" Inherits="ValidateCode" %>
4、生成验证码页面后台：
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;
/* Copyright all(c) 2005 ZhongFeng, http://blog.csdn.net/SW515 */
public partial class ValidateCode : System.Web.UI.Page
{
private void Page_Load(object sender, System.EventArgs e)
{
this.CreateCheckCodeImage(GenerateCheckCode());
}
#region Web 窗体设计器生成的代码
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: 该调用是 ASP.NET Web 窗体设计器所必需的。
//
InitializeComponent();
base.OnInit(e);
}
/// <summary>
/// 设计器支持所需的方法 - 不要使用代码编辑器修改
/// 此方法的内容。
/// </summary>
private void InitializeComponent()
{
this.Load += new System.EventHandler(this.Page_Load);
}
#endregion
private string GenerateCheckCode()
{
int number;
char code;
string checkCode = String.Empty;
System.Random random = new Random();
for (int i = 0; i < 5; i++)
{
number = random.Next();
if (number % 2 == 0)
code = (char)('0' + (char)(number % 10));
else
code = (char)('A' + (char)(number % 26));
checkCode += code.ToString();
}
Session["VNum"] = checkCode;
return checkCode;
}
private void CreateCheckCodeImage(string checkCode)
{
if (checkCode == null || checkCode.Trim() == String.Empty)
return;
System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);
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);
//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);
Response.ClearContent();
Response.ContentType = "image/Gif";
Response.BinaryWrite(ms.ToArray());
}
finally
{
g.Dispose();
image.Dispose();
}
}
}
红色字体为解说,不为代码!
首先在主页外建一个页面!假使我们命名为:VerifyChar.aspx
VerifyChar.aspx.cs中具体代码如下:
注意:VerifyChar.aspx的源中HTML代码无需修改!
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.IO;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
namespace YanZheng
{
/// <summary>
/// WebForm1 的摘要说明。
/// </summary>
///
public class WebForm1 : System.Web.UI.Page
{
private const float PI = 3.14159265358979f;
private const float PI2 = 6.28318530717959f;
private const int VCODENUM = 4; //验证码位数
private const int FONTSIZE = 14; //验证码字体大小
private const string VCHAR = "3,3,5,5,6,6,7,7,9,9,A,C,E,F,G,H,K,L,M,N,P,R,T,X,Y,Z"; //定义验证码字符及出现频次
private void Page_Load(object sender, System.EventArgs e)
{
// 在此处放置用户代码以初始化页面
Response.Cache.SetCacheability(System.Web.HttpCacheability.NoCache); //不缓存
float x, y, x1, y1;
int PenWidth1, PenWidth2, VerifyVharFont;
string VerifyChar = RndChar(); //RndChar是一个自定义函数
System.Drawing.Bitmap Img;
Graphics g;
Brush backBrush = Brushes.DimGray;
Brush textBrush = Brushes.Black;
VerifyVharFont = FONTSIZE; //验证码字符字体大小
Font textFont = new Font("Arial", VerifyVharFont, FontStyle.Strikeout); //验证码字体
MemoryStream ms;
int gWidth = Convert.ToInt32(VerifyChar.Length) * VerifyVharFont + VerifyVharFont; //验证区宽度。如果字符都为W，不加宽是不行的
Img = new System.Drawing.Bitmap(gWidth, 25); //验证区高度
//生成随机背景颜色
int nRed, nGreen, nBlue; // 背景的三元色
Random rd = new Random();
nRed = rd.Next(255) % 128 + 128;
nGreen = rd.Next(255) % 128 + 128;
nBlue = rd.Next(255) % 128 + 128;
//在图片框picCanvas上面建立一个新的空白Graphics
g = Graphics.FromImage(Img);
//填充位图背景
g.FillRectangle(new SolidBrush(System.Drawing.Color.FromArgb(nRed, nGreen, nBlue)), 0, 0, Img.Width, Img.Height);
//随机输出噪音线
for(int i = 0; i<3;i++)
{
Random rnd = new Random();
x = Img.Width * (float)rnd.NextDouble();
y = Img.Height * (float)rnd.NextDouble();
x1 = Img.Width * (float)rnd.NextDouble();
y1 = Img.Height * (float)rnd.NextDouble();
PenWidth1 = Convert.ToInt32(2 * rnd.NextDouble()); //修改参数可获得不同的效果
g.DrawLine(new Pen(backBrush, PenWidth1), x, y, x1, y1);
}
//随机输出噪点
PenWidth2 = 2; //修改参数可获得不同的效果
for(int i =0 ;i<10;i++)
{
Random rnd = new Random();
x = Img.Width * (float)rnd.NextDouble();
y = Img.Height * (float)rnd.NextDouble();
nRed = rd.Next(255) % 128 + 128;
nGreen = rd.Next(255) % 128 + 128;
nBlue = rd.Next(255) % 128 + 128;
g.DrawRectangle(new Pen(Color.FromArgb(nRed, nGreen, nBlue), PenWidth2), x, y, 1, 1);
}
//文字的位置
Random rnd2 = new Random();
x = 16 * (float)rnd2.NextDouble() - 6; //随机产生X轴位置，增加程序识别难度
y = 0;
//随机画3D背景
Random rnd3d = new Random();
double S3d = rnd3d.NextDouble();
if( S3d > 0.9)
{
for(int i = 1 ;i>0 ;i--)
{
g.DrawString(VerifyChar, textFont, backBrush, x - i, y + i);
}
}
//将全局变换平移(x, y)，也就是使画布上将要画的所有内容向左边移动x，向下移动y
g.TranslateTransform(1.5f, 1);
//做切变，将原始矩形的下边缘水平移动矩形高度的0.2倍
Matrix textTransform = g.Transform;
textTransform.Shear(0.2f, 0);
g.Transform = textTransform;
//画出文字
g.DrawString(VerifyChar, textFont, textBrush, x, y);
this.Session["VerifyChar"] = VerifyChar; //将验证字符写入Session，供前台调用
//扭曲验证字符。TwistImage参数可自行修改
int Twist1, Twist2;
if( S3d > 0.9)
{
Twist1 = 0;
Twist2 = 0;
}
else
{
Random rnd4 = new Random();
Twist1 = Convert.ToInt32(rnd4.NextDouble() * 3); //扭曲参数随机生成
Twist2 = Convert.ToInt32(rnd4.NextDouble() * 2); //扭曲参数随机生成
}
Img = TwistImage(Img, true, -Twist1, -Twist2);
Img = TwistImage(Img, false, Twist1, Twist2); //多扭曲几次也没关系，只是消耗服务器资源多些
ms = new MemoryStream();
Img.Save(ms, ImageFormat.Png);
Response.ClearContent(); //需要输出图象信息 要修改HTTP头
Response.ContentType = "image/Png";
Response.BinaryWrite(ms.ToArray());
g.Dispose();
Img.Dispose();
Response.End();
}
//函数名称:RndChar
//VCODENUM--设定返回随机字符串的位数
//函数功能:产生指定长度的由数字和字符组成的随机字符串
private string RndChar()
{
string[] VcArray = VCHAR.Split(','); //将字符串生成数组
int VCHARLen = VcArray.Length;
string vvchar = "";
Random rnd5 = new Random();
for(int i = 0; i < VCODENUM; i++) //确保最少2个字符，最多VCODENUM+1个字符
{
vvchar += VcArray[rnd5.Next(0,VCHARLen)]; //数组一般从0开始读取，所以这里为25*Rnd
}
return vvchar;
}
//函数名称:TwistImage
//函数参数: dMultValue－波形的幅度倍数；dPhase波形的起始相位，取值区间[0-2*PI)；bXDir－扭曲方式
//函数功能:正弦曲线Wave扭曲图片。函数可以迭加使用，以获得不同方式不同程度的效果
//这个天才的函数，已经无法考证出处了。感谢原作者！
private Bitmap TwistImage(Bitmap srcBmp , bool bXDir , double dMultValue , double dPhase )
{
Bitmap destBmp =new Bitmap(srcBmp.Width, srcBmp.Height);
double dBaseAxisLen = bXDir ? Convert.ToDouble(destBmp.Height): Convert.ToDouble(destBmp.Width);
for(int i = 0;i<destBmp.Width;i++)
{
for(int j = 0;j<destBmp.Height;j++)
{
double dx = 0;
dx = bXDir ? PI2 * Convert.ToDouble(j) / dBaseAxisLen : PI2 * Convert.ToDouble(i) / dBaseAxisLen;
dx += dPhase;
double dy = Math.Sin(dx);
//取得当前点的颜色
int nOldX = 0;
int nOldY = 0;
nOldX = bXDir ? i + Convert.ToInt32(dy * dMultValue) : i;
nOldY = bXDir ? j: j + Convert.ToInt32(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;
}
}
}
续接下文........
· 在登陆页面Default.aspx的源中输入如下代码:
<div>
<asp:TextBox ID="TextBox1" runat="server"></asp:TextBox>
<asp:ImageButton ID="Image1" runat="server" ImageUrl="VerifyChar.aspx" /><br>
<br>
<asp:Button ID="Button1" runat="server" Text="提交" />
</div>
在登陆页面Default.aspx.cs中输入如下代码:
private void Page_Load(object sender, System.EventArgs e)
{
// 在此处放置用户代码以初始化页面
if( Request.Form["TextBox1"] != "" && this.IsPostBack)
{
if( Session["VerifyChar"].ToString() == Request.Form["TextBox1"])
Response.Write("成功");
else
Response.Write("失败");
}
}
private void Image1_Click(object sender, System.Web.UI.ImageClickEventArgs e)
{
Image1.ImageUrl = "VerifyChar.aspx";
}