Home > Article > Backend Development > Development of non-refresh verification code in ASP.NET
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Login.aspx.cs" Inherits="Login" %>
<!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>无标题页</title>
<script type="text/javascript">
function DoFresh() {
document.getElementById("Image1").src = "VerifyCode.aspx";
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<table>
<tr>
<td>
验证码：<asp:TextBox ID="txtValidateCode" runat="server"></asp:TextBox>
</td>
<td>
<asp:Image ID="Image1" runat="server" />
<a href="javascript:DoFresh();">看不清?</a>
</td>
</tr>
<tr>
<td align="center" colspan="2">
<br />
<asp:Literal ID="litErrorMsg" runat="server"></asp:Literal>
<asp:Button ID="btnSubmit" runat="server" Text="确定" onclick="btnSubmit_Click" />
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
public partial class Login : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
if (!Page.IsPostBack)
{
Image1.ImageUrl = "VerifyCode.aspx";
}
}
protected void btnSubmit_Click(object sender, EventArgs e)
{
if (Session["ValidateCode"] != null)
{
string outputValidateCode = Session["ValidateCode"] as string;
string inputValidateCode = txtValidateCode.Text.Trim();
if (string.Compare(outputValidateCode, inputValidateCode, true) != 0)
{
//Response.Write("<script>javascript:alert('输入的验证码错误！');</script>");
litErrorMsg.Text = "输入的验证码错误！";
}
else
{
//Response.Write("<script>javascript:alert('输入的验证码正确！');</script>");
litErrorMsg.Text = "输入的验证码正确！";
}
}
}
#region 调用下面的方法实现客户端保存Cookie验证模式
private void ValidateMethod()
{
if (Request.Cookies["CheckCode"] == null)
{
litErrorMsg.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。";
litErrorMsg.Visible = true;
return;
}
if (String.Compare(Request.Cookies["CheckCode"].Value, TextBox1.Text.ToString().Trim(), true) != 0)
{
litErrorMsg.Text = "<font color=red>对不起，验证码错误！</font>";
litErrorMsg.Visible = true;
return;
}
else
{
litErrorMsg.Text = "<font color=green>恭喜，验证码输入正确！</font>";
litErrorMsg.Visible = true;
}
}
#endregion
}
//VerifyCode.aspx is the code generated by default
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.WebParts;
using System.Web.UI.HtmlControls;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
using System.IO;
public partial class VerifyCode : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
//GenerateValidateCode();
GenerateVerifyImage(4);//GenerateVerifyImage(int length)
}
#region 【无刷新仿google波形扭曲彩色】验证码样式0___GenerateValidateCode()
private void GenerateValidateCode()
{
this.Length = this.length;
this.FontSize = this.fontSize;
this.Chaos = this.chaos;
this.BackgroundColor = this.backgroundColor;
this.ChaosColor = this.chaosColor;
this.CodeSerial = this.codeSerial;
this.Colors = this.colors;
this.Fonts = this.fonts;
this.Padding = this.padding;
string VNum = this.CreateVerifyCode(); //取随机码
Session["ValidateCode"] = VNum.ToUpper();//取得验证码，以便后来验证
this.CreateImageOnPage(VNum, this.Context); // 输出图片
//Cookie验证模式， 使用Cookies取验证码的值
//Response.Cookies.Add(new HttpCookie("CheckCode", code.ToUpper()));
}
#endregion
#region 验证码长度(默认4个验证码的长度)
int length = 4;
public int Length
{
get { return length; }
set { length = value; }
}
#endregion
#region 验证码字体大小(为了显示扭曲效果，默认40像素，可以自行修改)
int fontSize = 22;
public int FontSize
{
get { return fontSize; }
set { fontSize = value; }
}
#endregion
#region 边框补(默认1像素)
int padding = 2;
public int Padding
{
get { return padding; }
set { padding = value; }
}
#endregion
#region 是否输出燥点(默认不输出)
bool chaos = true;
public bool Chaos
{
get { return chaos; }
set { chaos = value; }
}
#endregion
#region 输出燥点的颜色(默认灰色)
Color chaosColor = Color.LightGray;
public Color ChaosColor
{
get { return chaosColor; }
set { chaosColor = value; }
}
#endregion
#region 自定义背景色(默认白色)
Color backgroundColor = Color.White;
public Color BackgroundColor
{
get { return backgroundColor; }
set { backgroundColor = value; }
}
#endregion
#region 自定义随机颜色数组
Color[] colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
public Color[] Colors
{
get { return colors; }
set { colors = value; }
}
#endregion
#region 自定义字体数组
string[] fonts = { "Arial", "Georgia" };
public string[] Fonts
{
get { return fonts; }
set { fonts = value; }
}
#endregion
#region 自定义随机码字符串序列(使用逗号分隔)
string codeSerial = "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";
public string CodeSerial
{
get { return codeSerial; }
set { codeSerial = value; }
}
#endregion
#region 产生波形滤镜效果
private const double PI = 3.1415926535897932384626433832795;
private const double PI2 = 6.283185307179586476925286766559;
/// <summary>
/// 正弦曲线Wave扭曲图片
/// </summary>
/// <param name="srcBmp">图片路径</param>
/// <param name="bXDir">如果扭曲则选择为True</param>
/// <param name="nMultValue">波形的幅度倍数，越大扭曲的程度越高，一般为3</param>
/// <param name="dPhase">波形的起始相位，取值区间[0-2*PI)</param>
/// <returns></returns>
public Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
{
Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);
// 将位图背景填充为白色
System.Drawing.Graphics graph = Graphics.FromImage(destBmp);
graph.FillRectangle(new SolidBrush(Color.White), 0, 0, destBmp.Width, destBmp.Height);
graph.Dispose();
double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width;
for (int i = 0; i < destBmp.Width; i++)
{
for (int j = 0; j < destBmp.Height; j++)
{
double dx = 0;
dx = bXDir ? (PI2 * (double)j) / dBaseAxisLen : (PI2 * (double)i) / dBaseAxisLen;
dx += dPhase;
double dy = Math.Sin(dx);
// 取得当前点的颜色
int nOldX = 0, nOldY = 0;
nOldX = bXDir ? i + (int)(dy * dMultValue) : i;
nOldY = bXDir ? j : j + (int)(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;
}
#endregion
#region 生成校验码图片
public Bitmap CreateImageCode(string code)
{
int fSize = FontSize;
int fWidth = fSize + Padding;
int imageWidth = (int)(code.Length * fWidth) + 4 + Padding * 2;
int imageHeight = fSize * 2 + Padding;
System.Drawing.Bitmap image = new System.Drawing.Bitmap(imageWidth, imageHeight);
Graphics g = Graphics.FromImage(image);
g.Clear(BackgroundColor);
Random rand = new Random();
//给背景添加随机生成的燥点
if (this.Chaos)
{
Pen pen = new Pen(ChaosColor, 0);
int c = Length * 10;
for (int i = 0; i < c; i++)
{
int x = rand.Next(image.Width);
int y = rand.Next(image.Height);
g.DrawRectangle(pen, x, y, 1, 1);
}
}
int left = 0, top = 0, top1 = 1, top2 = 1;
int n1 = (imageHeight - FontSize - Padding * 2);
int n2 = n1 / 4;
top1 = n2;
top2 = n2 * 2;
Font f;
Brush b;
int cindex, findex;
//随机字体和颜色的验证码字符
for (int i = 0; i < code.Length; i++)
{
cindex = rand.Next(Colors.Length - 1);
findex = rand.Next(Fonts.Length - 1);
f = new System.Drawing.Font(Fonts[findex], fSize, System.Drawing.FontStyle.Bold);
b = new System.Drawing.SolidBrush(Colors[cindex]);
if (i % 2 == 1)
{
top = top2;
}
else
{
top = top1;
}
left = i * fWidth;
g.DrawString(code.Substring(i, 1), f, b, left, top);
}
//画一个边框 边框颜色为Color.Gainsboro
g.DrawRectangle(new Pen(Color.Gainsboro, 0), 0, 0, image.Width - 1, image.Height - 1);
g.Dispose();
//产生波形（Add By 51aspx.com）
image = TwistImage(image, true, 4, 4);
return image;
}
#endregion
#region 将创建好的图片输出到页面
public void CreateImageOnPage(string code, HttpContext context)
{
Response.BufferOutput = true; //特别注意
Response.Cache.SetExpires(DateTime.Now.AddMilliseconds(-1));//特别注意
Response.Cache.SetCacheability(HttpCacheability.NoCache);//特别注意
Response.AppendHeader("Pragma", "No-Cache"); //特别注意
MemoryStream ms = new MemoryStream();
Bitmap image = this.CreateImageCode(code);
image.Save(ms, ImageFormat.Jpeg);
Response.ClearContent();
Response.ContentType = "image/JPEG";
Response.BinaryWrite(ms.ToArray());
Response.End();
ms.Close();
ms = null;
image.Dispose();
image = null;
}
#endregion
#region 生成随机字符码
public string CreateVerifyCode(int codeLen)
{
if (codeLen == 0)
{
codeLen = Length;
}
string[] arr = CodeSerial.Split(',');
string code = "";
int randValue = -1;
Random rand = new Random(unchecked((int)DateTime.Now.Ticks));
for (int i = 0; i < codeLen; i++)
{
randValue = rand.Next(0, arr.Length - 1);
code += arr[randValue];
}
return code;
}
public string CreateVerifyCode()
{
return CreateVerifyCode(0);
}
#endregion
#region 另一种验证码样式 GenerateVerifyImage(int length)
/// <summary>
/// 将创建好的图片输出到页面
/// </summary>
public void GenerateVerifyImage(int nLen)
{
string validateCode = "";//生成的验证码
int nBmpWidth = GetImagewidth(nLen);
int nBmpHeight = GetImageHeight();
System.Drawing.Bitmap bmp = new System.Drawing.Bitmap(nBmpWidth, nBmpHeight);
//对图像进行弯曲
TwistImage(bmp, true, 12, 2);
// 1. 生成随机背景颜色
int nRed, nGreen, nBlue; // 背景的三元色
System.Random rd = new Random((int)System.DateTime.Now.Ticks);
nRed = rd.Next(255) % 128 + 128;
nGreen = rd.Next(255) % 128 + 128;
nBlue = rd.Next(255) % 128 + 128;
// 2. 填充位图背景
System.Drawing.Graphics graph = System.Drawing.Graphics.FromImage(bmp);
graph.FillRectangle(new SolidBrush(System.Drawing.Color.FromArgb(nRed, nGreen, nBlue))
, 0
, 0
, nBmpWidth
, nBmpHeight);
// 3. 绘制干扰线条，采用比背景略深一些的颜色
int nLines = 3;
System.Drawing.Pen pen = new System.Drawing.Pen(System.Drawing.Color.FromArgb(nRed - 17, nGreen - 17, nBlue - 17), 2);
for (int a = 0; a < nLines; a++)
{
int x1 = rd.Next() % nBmpWidth;
int y1 = rd.Next() % nBmpHeight;
int x2 = rd.Next() % nBmpWidth;
int y2 = rd.Next() % nBmpHeight;
graph.DrawLine(pen, x1, y1, x2, y2);
}
// 采用的字符集，可以随即拓展，并可以控制字符出现的几率
string strCode = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
// 4. 循环取得字符，并绘制
for (int i = 0; i < nLen; i++)
{
int x = (i * 13 + rd.Next(3));
int y = rd.Next(4) + 1;
// 确定字体
System.Drawing.Font font = new System.Drawing.Font("Courier New",//文字字体类型
12 + rd.Next() % 4,//文字字体大小
System.Drawing.FontStyle.Bold);//文字字体样式
char c = strCode[rd.Next(strCode.Length)]; // 随机获取字符
validateCode += c.ToString();
// 绘制字符
graph.DrawString(c.ToString(),
font,
new SolidBrush(System.Drawing.Color.FromArgb(nRed - 60 + y * 3, nGreen - 60 + y * 3, nBlue - 40 + y * 3)),
x,
y);
}
Session["ValidateCode"] = validateCode;
//对图像进行弯曲
TwistImage(bmp, true, 4, 4);
Response.BufferOutput = true; //特别注意
Response.Cache.SetExpires(DateTime.Now.AddMilliseconds(-1));//特别注意
Response.Cache.SetCacheability(HttpCacheability.NoCache);//特别注意
Response.AppendHeader("Pragma", "No-Cache"); //特别注意
// 5. 输出字节流
MemoryStream bstream = new MemoryStream();
bmp.Save(bstream, ImageFormat.Jpeg);
Response.ClearContent();
Response.ContentType = "image/JPEG";
Response.BinaryWrite(bstream.ToArray());
Response.End();
bstream.Close();
bstream = null;
bmp.Dispose();
bmp = null;
graph.Dispose();
}
///<summary>
///得到验证码图片的宽度
///</summary>
///<paramname="validateNumLength">验证码的长度</param>
///<returns></returns>
public static int GetImagewidth(int validateNumLength)
{
return (int)(13 * validateNumLength + 5);
}
///<summary>
///得到验证码的高度
///</summary>
///<returns></returns>
public static int GetImageHeight()
{
return 25;
}
#endregion
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