求asp.net验证码代码
简单点就行,我不会这个。能说下解释更好。
简单点就行,我不会这个。能说下解释更好。
答案:
using System;
using System.Collections;
using System.Configuration;
using System.Data;
using System.Linq;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Xml.Linq;
using System.Drawing;
using System.Drawing.Imaging;
public partial class Admin_Validata : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
Session["code"] = RandNum(4);
ValidateCode(Session["code"].ToString(), 40, 20, "黑体", 10, "#FFFFFF");
}
/// <summary>
/// 该方法用于生成指定位数的随机数
/// </summary>
/// <param name="VcodeNum">参数是随机数的位数</param>
/// <returns>返回一个随机数字符串</returns>
private string RandNum(int VcodeNum)
{
string Vchar = "0,1,2,3,4,5,6,7,8,9";
string[] VcArray = Vchar.Split(',');//拆分成数组
string VNum = "";
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 = 0; i < VcodeNum; 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 RandNum(VcodeNum);
}
temp = t;
VNum += VcArray[t];
}
return VNum;
}
/// <summary>
/// 生成图片并写入字符
/// </summary>
/// <param name="VNum">目标字符</param>
/// <param name="w">宽</param>
/// <param name="h">高</param>
/// <param name="font">字体文件</param>
/// <param name="fontSize">字体大小</param>
/// <param name="bgColor">图片背景颜色</param>
private void ValidateCode(string VNum, int w, int h, string font, int fontSize, string bgColor)
{
Bitmap Img = new Bitmap(w, h);//生成图像的实例
Graphics g = Graphics.FromImage(Img);//从Img对象生成新的Graphics对象
g.Clear(ColorTranslator.FromHtml(bgColor));//背景颜色
Font f = new Font(font, fontSize);//生成Font类的实例
SolidBrush s = new SolidBrush(Color.Black);//生成笔刷类的实例
g.DrawString(VNum, f, s, 3, 3);//将VNum写入图片中
Img.Save(Response.OutputStream, ImageFormat.Jpeg);//将此图像以Jpeg图像文件的格式保存到流中
Response.ContentType = "image/Jpeg";
//回收资源
g.Dispose();
Img.Dispose();
Response.End();
}
}前台:
<%@ Page language="c#" CodeFile="checkimg.aspx.cs" Inherits="testnet.checkimg" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN" >
<HTML>
<HEAD>
<title>checkimg</title>
<meta name="GENERATOR" Content="Microsoft Visual Studio .NET 7.1">
<meta name="CODE_LANGUAGE" Content="C#">
<meta name="vs_defaultClientScript" content="JavaScript">
<meta name="vs_targetSchema" content=" http://schemas.microsoft.com/intellisense/ie5">
</HEAD>
<body>
<form id="Form1" method="post" runat="server">
</form>
</body>
</HTML>后台:
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Drawing.Imaging;namespace testnet
{
/// <summary>
/// checkimg 的摘要说明。
/// </summary>
public partial class checkimg : System.Web.UI.Page
{
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 (!this.Page.IsPostBack)
{
CreateCheckCodeImage();
}
}#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/// <summary>
/// 生成随机数
/// </summary>
/// <returns></returns>
private string GenerateCheckCode()
{
#region
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();
}HttpContext.Current.Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));
return checkCode;
#endregion
}/// <summary>
/// 生成验证码图片
/// </summa
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