生成验证码(数字字母混合)

CheckCode.aspx页面其实什么也不用写

<%@ Page Language="C#"  CodeFile="CheckCode.aspx.cs" Inherits="ValidateCode" %>



<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.1//EN" "http://www.w3.org/TR/xhtml11/DTD/xhtml11.dtd">

<html xmlns="http://www.w3.org/1999/xhtml">

<head runat="server">

    <title>Untitled Page</title>

</head>

<body>

    <form id="form1" runat="server">

       

    </form>

</body>

</html>

CheckCode.aspx.cs页面代码,生成验证码的主要部分

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;

using System.Drawing;



 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["CheckCodeImage"] = 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();

         }

     }

 }

下一步我们来引用上面的生成验证码页面(太简单不多说)

                       <asp:Label ID="labFlag" runat="server" Text="Label"></asp:Label>

                       <asp:TextBox ID="txtYz_Code" runat="server" MaxLength="5" Width="55px" BorderColor="Gray" BorderWidth="1px"></asp:TextBox>

                       <img title="看不清点击换一张" align="absMiddle" onclick="this.src=this.src+'?'" src="PassWord/CheckCode.aspx" />

 

后台判断

        if (String.Compare(Session["CheckCodeImage"].ToString(), this.txtYz_Code.Text.Trim().ToUpper(), true) != 0)

        {

            this.labFlag.text = "验证码错误,请输入正确的验证码。";

        }

 

 

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