前台代码：
<asp:TextBox ID="tbck" runat="server" Width="107px" SkinID="worm"></asp:TextBox>
<img alt="看不清？点击更换" onclick="this.src=this.src+'?'" src="VerifyCode.aspx" />
<asp:Button ID="Button1" runat="server" OnClick="Button1_Click" Text="Button" />后台代码：
if (this.tbck.Text == Request.Cookies["vCode"].Value)
{
Response.Write("相等");
}
//////VerifyCode.aspx
后台代码：
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 VerifyCode : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
VerifyCode v = new VerifyCode();
v.Length = this.length;
v.FontSize = this.fontSize;
v.Chaos = this.chaos;
v.BackgroundColor = this.backgroundColor;
v.ChaosColor = this.chaosColor;
v.CodeSerial = this.codeSerial;
v.Colors = this.colors;
v.Fonts = this.fonts;
v.Padding = this.padding;
string code = v.CreateVerifyCode(); // 取随机码
v.CreateImageOnPage(code, this.Context); // 输出图片
Response.Cookies.Add(new HttpCookie("vCode", code)); // 使用Cookies取验证码的值
}
//验证码长度(默认6个验证码的长度)
int length = 4;
public int Length
{
get { return length; }
set { length = value; }
}
//验证码字体大小(为了显示扭曲效果，默认20像素，可以自行修改)
int fontSize = 12;
public int FontSize
{
get { return fontSize; }
set { fontSize = value; }
}
//边框补(默认1像素)
int padding = 1;
public int Padding
{
get { return padding; }
set { padding = value; }
}
//是否输出燥点(默认为输出)
bool chaos = true;
public bool Chaos
{
get { return chaos; }
set { chaos = value; }
}
//输出燥点的颜色(默认灰色)
Color chaosColor = Color.LightGray;
public Color ChaosColor
{
get { return chaosColor; }
set { chaosColor = value; }
}
//自定义背景色(默认白色)
Color backgroundColor = Color.White;
public Color BackgroundColor
{
get { return backgroundColor; }
set { backgroundColor = value; }
}
//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; }
}
//自定义字体数组
string[] fonts = { "Arial", "Georgia" };
public string[] Fonts
{
get { return fonts; }
set { fonts = value; }
}
//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";
string codeSerial = "0,1,2,3,4,5,6,7,8,9";
public string CodeSerial
{
get { return codeSerial; }
set { codeSerial = value; }
}
//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 * 15;
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.White
g.DrawRectangle(new Pen(Color.White, 0), 0, 0, image.Width - 1, image.Height - 1);
g.Dispose();
return image;
}
//将创建好的图片输出到页面
public void CreateImageOnPage(string code, HttpContext context)
{
System.IO.MemoryStream ms = new System.IO.MemoryStream();
Bitmap image = this.CreateImageCode(code);
image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
context.Response.ClearContent();
context.Response.ContentType = "image/jpeg";
context.Response.BinaryWrite(ms.GetBuffer());
ms.Close();
ms = null;
image.Dispose();
image = null;
}
//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);
}
}
/// <summary>
/// 数学算式的验证码
/// http://www.zu14.cn/2008/11/22/net_math_vc/
/// Author: DeltaCat (三角猫)
/// </summary>
public sealed class MathVerifyCode
{
#region 生成图片
/// <summary>
/// 输出验证码表达式到浏览器
/// </summary>
/// <param name="context">httpcontext</param>
/// <param name="sessionKey">保存运算值的SESSION的KEY</param>
public void OutputImage(System.Web.HttpContext context, string sessionKey)
{
int mathResult = 0;
string expression = null;
Random rnd = new Random();
////生成3个10以内的整数，用来运算
int operator1 = rnd.Next(0, 10);
int operator2 = rnd.Next(0, 10);
int operator3 = rnd.Next(0, 10);
////随机组合运算顺序，只做 + 和 * 运算
switch (rnd.Next(0, 3))
{
case 0:
mathResult = operator1 + operator2 * operator3;
expression = string.Format("{0} + {1} * {2} = ?", operator1, operator2, operator3);
break;
case 1:
mathResult = operator1 * operator2 + operator3;
expression = string.Format("{0} * {1} + {2} = ?", operator1, operator2, operator3);
break;
default:
mathResult = operator2 + operator1 * operator3;
expression = string.Format("{0} + {1} * {2} = ?", operator2, operator1, operator3);
break;
}
using (Bitmap bmp = new Bitmap(150, 25))
{
using (Graphics graph = Graphics.FromImage(bmp))
{
graph.Clear(Color.FromA#e8eef7); ////背景色，可自行设置
////画噪点
for (int i = 0; i <= 128; i++)
{
graph.DrawRectangle(
new Pen(Color.FromArgb(rnd.Next(0, 255), rnd.Next(0, 255), rnd.Next(0, 255))),
rnd.Next(2, 128),
rnd.Next(2, 38),
1,
1);
}
////输出表达式
for (int i = 0; i < expression.Length; i++)
{
graph.DrawString(expression.Substring(i, 1),
new Font(FontFamily.GenericSansSerif, 12, FontStyle.Bold),
new SolidBrush(Color.FromArgb(rnd.Next(255), rnd.Next(128), rnd.Next(255))),
5 + i * 10,
rnd.Next(1, 5));
}
////画边框，不需要可以注释掉
graph.DrawRectangle(new Pen(Color.Firebrick), 0, 0, 150 - 1, 25 - 1);
}
context.Session[sessionKey] = mathResult; ////将运算结果存入session
////禁用缓存
DisableHttpCache(context);
////输出图片到浏览器，我采用的是 gif 格式，可自行设置其他格式
context.Response.ContentType = "image/gif";
bmp.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Gif);
context.Response.End();
}
}
#endregion
/// <summary>
/// 禁用缓存
/// </summary>
/// <param name="context">httpcontext</param>
private static void DisableHttpCache(System.Web.HttpContext context)
{
////清除http缓存
context.Response.ClearHeaders();
context.Response.ClearContent();
////禁用http缓存
//// http 1.1
context.Response.AddHeader("Expires", "Mon, 26 Jul 1997 05:00:00 GMT");
context.Response.AddHeader("Cache-Control", "no-store, no-cache, max-age=0, must-revalidate");
//// http 1.0
context.Response.AddHeader("Pragma", "no-cache");
}
}注： 如果觉得验证码太模糊，可以将画噪点的地方调整为下面的：
for (int i = 0; i <= 128; i++)
{
graph.DrawRectangle(
new Pen(Color.FromArgb(rnd.Next(0, 255), rnd.Next(0, 255), rnd.Next(0, 255))),
(float)rnd.Next(2, 128),
(float)rnd.Next(2, 38),
0.5F, //噪点的粒度
0.5F);//噪点的粒度，可以调节这两个值，到认为自己满意
}
//新建一个 ashx 页面，例如： Mvc.ashx
//记得此ashx文件的类，一定要继承 System.Web.SessionState.IRequiresSessionState 才可以使用session
public class Mvc : IHttpHandler, System.Web.SessionState.IRequiresSessionState
{
public void ProcessRequest (HttpContext context) {
MathVerifyCode mvc = new MathVerifyCode();
mvc.OutputImage(context, "mvc");
}
public bool IsReusable {
get {
return true;
}
}
}
在需要显示验证码的地方，加入：
<img src="mvc.aspx" alt=""/>或者<img src="mvc.ashx" alt=""/>
