验证码实现

这里贴一段验证码的代码，只做记录，方便直接使用。

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using System.Web.UI;

using System.Web.UI.WebControls;

using System.Drawing;

using System.IO;

using System.Drawing.Imaging;



namespace Elink.Web.Authencation.CheckCode

{

    public partial class SafeCode : System.Web.UI.Page

    {

        protected void Page_Load(object sender, EventArgs e)

        {

            string chkCode = string.Empty;

            //颜色列表，用于验证码、噪线、噪点 

            Color[] color = new Color[] { Color.Black, Color.Red, Color.Blue, Color.Green, Color.Orange, Color.Brown, Color.Brown, Color.DarkBlue };

            //字体列表，用于验证码 

            string[] font = new string[] { "Times New Roman", "MS Mincho", "Book Antiqua", "Gungsuh", "PMingLiU", "Impact" };

            //验证码的字符集，去掉了一些容易混淆的字符 

            char[] character = { '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X', 'Y' };



            Random rnd = new Random();



            //生成验证码字符串 

            for (int i = 0; i < 4; i++)

            {

                chkCode += character[rnd.Next(character.Length)];

            }

            Session["CheckCode"] = chkCode;



            Bitmap bmp = new Bitmap(100, 20);

            Graphics g = Graphics.FromImage(bmp);

            g.Clear(Color.White);



            //画噪线 

            for (int i = 0; i < 5; i++)

            {

                int x1 = rnd.Next(100);

                int y1 = rnd.Next(20);

                int x2 = rnd.Next(100);

                int y2 = rnd.Next(20);

                Color clr = color[rnd.Next(color.Length)];

                g.DrawLine(new Pen(clr), x1, y1, x2, y2);

            }



            //画验证码字符串 

            for (int i = 0; i < chkCode.Length; i++)

            {

                string f = font[rnd.Next(font.Length)];

                Font ft = new Font(f, 12);



                Color clr = color[rnd.Next(color.Length)];

                g.DrawString(chkCode[i].ToString(), ft, new SolidBrush(clr), i * 20 + 8, 4);

            }



            //画噪点 

            for (int i = 0; i < 40; i++)

            {

                int x = rnd.Next(bmp.Width);

                int y = rnd.Next(bmp.Height);

                Color clr = color[rnd.Next(color.Length)];

                bmp.SetPixel(x, y, clr);

            }

            //清除该页输出缓存，设置该页无缓存 

            Response.Buffer = true;

            Response.ExpiresAbsolute = DateTime.Now.AddMilliseconds(0);

            Response.Expires = 0;

            Response.CacheControl = "no-cache";

            Response.AddHeader("Pragma", "No-Cache");



            //将验证码图片写入内存流，并将其以 "image/Png" 格式输出 

            MemoryStream ms = new MemoryStream();



            try

            {

                bmp.Save(ms, ImageFormat.Png);

                Response.ClearContent();

                Response.ContentType = "image/Png";

                Response.BinaryWrite(ms.ToArray());

                Response.End();

            }

            finally

            {

                ////显式释放资源 

                bmp.Dispose();

                g.Dispose();

            }



        }

    }

}

View Code

获取session保存的验证码内容

using System;

using System.Collections.Generic;

using System.Linq;

using System.Web;

using NAIS.Common;

using Elink.Common;

using System.Web.Script.Serialization;

using System.Web.SessionState;



namespace Elink.Web.RelationService

{

    /// <summary>

    /// LoginGetCheckCodeValue 的摘要说明

    /// </summary>

    public class LoginGetCheckCodeValue : IHttpHandler, IRequiresSessionState

    {



        public void ProcessRequest(HttpContext context)

        {

            //控件ID

            string returnFlag = context.Request["returnFlag"];

            try

            {

                string reValue = string.Empty;

                if (returnFlag.ToUpper() == "CHECKCODE")

                {

                    reValue = SessionUtils.GetSessionValue(context.Session["CheckCode"]);

                }

                JavaScriptSerializer jsSerializer = new JavaScriptSerializer();

                string json = jsSerializer.Serialize(new { result = true, Data = reValue });

                context.Response.ContentType = "text/plain";

                context.Response.Write(json);

            }

            catch (Exception ex)

            {

                LogUtil.Logger.Error(string.Format("用户登录一般处理程序LoginGetCheckCodeValue：ProcessRequest获取指定返回值异常，指定返回值为={0}", returnFlag), ex);

            }

        }



        public bool IsReusable

        {

            get

            {

                return false;

            }

        }

    }

}

View Code