ASP.NET图片验证码学习!

8/10/2015来源:ASP.NET技巧人气:1519

asp.net图片验证码学习!

1. 新建一个Validate.aspx,然后在Validate.aspx.cs编写代码:

using System;using System.Collections;using System.ComponentModel;using System.Data;using System.Web;using System.Drawing;using System.Web.sessionState;using System.Web.UI;using System.Web.UI.WebControls;using System.Web.UI.HtmlControls;using System.Drawing.Imaging;using System.IO;

public partial class Validate : System.Web.UI.Page{   PRotected void Page_Load(object sender, EventArgs e)   {   this.CreateCheckCodeImage(RndNum());

  }   private string RndNum()   {   int number;   char code;   string checkCode = String.Empty;

   System.Random random = new Random();

   for (int i = 0; i < 4; 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["CheckCode"] = 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);   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();     }   }

}

2. 在前台你想添加的页面添加这段代码:(我这里假设是在登录页面Login.aspx中添加图片验证码)

<img id="ImageCode" src="../Validate.aspx" style="cursor:pointer" onmouseup="RefreshImage()" alt="点击重刷新"/>

还需要在<head>...</head>之间添加这段代码:

<script language ="javascript" type="text/Javascript" >   function RefreshImage()

{     var img = document.getElementById("ImageCode"); // 这里的ImageCode就是上面你取图片的Id名字,这里要一致!     img.src = img.src + '?';   } </script>

3. 在后台Login.aspx.cs中添加实现代码:

引用......

public partial class Login : System.Web.UI.Page{   protected void Page_Load(object sender, EventArgs e)   {

  }

  // 登录按钮点击事件处理   protected void btnLogin_Click(object sender, ImageClickEventArgs e)   {     User user = new User();     user.LoginId = this.txt_LoginId.Text.Trim();     user.LoginPwd = this.txt_LoginPwd.Text.Trim();     if (this.txtCode.Text.ToLower() == Session["CheckCode"].ToString().ToLower())     {       Response.Redirect("Index.aspx");

      else       {         Session["user"] = null;         this.Page.ClientScript.RegisterStartupScript(this.GetType(), "str", "<script>alert(\"登录失败!!\")</script>");       }     }     else     {       this.Page.ClientScript.RegisterStartupScript(this.GetType(), "str", "<script>alert(\"验证码错误!!\")</script>");     }

  }

  // 新用户注册按钮点击事件处理   protected void btn_Register_Click(object sender, ImageClickEventArgs e)   {     Response.Redirect("Register.aspx");   }}

最后运行出来的验证码就是这个样子的~~

当然如果你想实现在其他页面上代码会有些小的变动,但是基本代码就这些~~

Thanks~~