Login 图片验证码 生成一个图片验证控件

第一种是：可以产生图片的图片验证码

1、类库文件

<ccid_nobr>

<ccid_code>using System;
    using System.Collections.Generic;
    using System.Linq;
    using System.Text;
    using System.Web.UI.WebControls;
    using System.ComponentModel; 
    using System.Web.UI;

    namespace AuthCode
    {
    [Description("图形验证码控件"),
ToolboxData("<{0}:ImageAuthCode runat=server>
</{0}:ImageAuthCode>")]
    public class ImageAuthCode:Image
    {
        [Description("图形验证码产生网页地址"), DefaultValue("")]
        public string ValidateCodeUrl { get; set; }

        protected override void Render(HtmlTextWriter writer)
        {
            string sUrl, sScript;

            sUrl = this.ValidateCodeUrl;

            if (string.IsNullOrEmpty(sUrl))
            {
                sUrl = "~/AuthCode.ashx";
            }

            if (this.BorderWidth == Unit.Empty)
            {
                this.BorderWidth = Unit.Pixel(1);
            }

            if (this.AlternateText == string.Empty)
            {
                this.AlternateText = "图形验证码";
            }

            this.ToolTip = "鼠标单击可以产生新的验证码";
            this.ImageUrl = sUrl;

            if (!this.DesignMode)
            {
                sScript = String.Format("this.src='{0}?
flag='+Math.random();", 
this.Page.ResolveClientUrl(sUrl));
                this.Attributes["onclick"] = sScript;
            }

            this.Style[HtmlTextWriterStyle.Cursor] = "pointer";

            base.Render(writer);
        }

        public bool ValidateCode(string Code)
        {
            if (this.Page.Session["CheckCode"] == null)
                return false;

            if (this.Page.Session["CheckCode"].ToString() == Code)
            {
                return true;
            }
            else
            {
                return false;
            }
        }
    }
}

2、ashx文件如下

<ccid_nobr>

<ccid_code>using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Drawing;
using System.Web.SessionState;

namespace MyAuthCode
{
    /// <summary>
    /// Summary description for AuthCode
    /// </summary>
    public class AuthCode : IHttpHandler, IRequiresSessionState 
    {
        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("Verdana", 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);
                HttpContext.Current.Response.ClearContent();
                HttpContext.Current.Response.ContentType = "image/Gif";
                HttpContext.Current.Response.BinaryWrite(ms.ToArray());
            }
            finally
            {
                g.Dispose();
                image.Dispose();
            }
        }

        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();
            }
            
            HttpContext.Current.Session.Add("CheckCode", checkCode.Trim().ToLower());
            //将 checkCode 写入 Session 中

            return checkCode;
        }

        public void ProcessRequest(HttpContext context)
        {
            this.CreateCheckCodeImage(GenerateCheckCode());
        }

        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
    }
}

3、增加工具箱和拖到页面使用

<ccid_nobr>

<ccid_code><%@ Register assembly="AuthCode" namespace="AuthCode" tagprefix="cc1" %>
<cc1:ImageAuthCode ID="ImageAuthCode1" runat="server" Height="20px" Width="100px"/>

4、验证方法

<ccid_nobr>

<ccid_code>ImageAuthCode1.ValidateCode(TextBox1.Text.Trim().ToString()) 结果返回true或者false.

5、最重要的一点修改Web.Config配置文件

<ccid_nobr>

<ccid_code><location path="AuthCode.ashx">
    <system.web>
      <authorization>
        <allow users="*"/>
      </authorization>
    </system.web>
  </location>

如果不增加此段代码，当你的时，图片验证码是无法显示的