动态加载验证码

1.创建一般应用程序ashx

<%@ WebHandler Language="C#" Class="YZM" %>

using System;
using System.Web;

public class YZM : IHttpHandler,System .Web.SessionState .IRequiresSessionState{

    public void ProcessRequest (HttpContext context) {
       //动态生成图片
        context.Response.ContentType = "image/JPEG";
        using (System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(100, 30))
        {
            using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap))
            {
                /*
                 g.DrawString("验证码", new System.Drawing.Font("宋体", 10), System.Drawing.Brushes .Red , new System.Drawing.PointF(0, 0));
                 bitmap .Save (context .Response .OutputStream ,System .Drawing.Imaging.ImageFormat .Jpeg) ;
                 */
                //动态产生随机数
                Random rand = new Random();
                int code = rand.Next();
                string strCode = code.ToString();
                HttpContext.Current.Session["Code"] = strCode;
                g.DrawString(strCode, new System.Drawing.Font("宋体", 12), System.Drawing.Brushes.Green, new System.Drawing.PointF(0, 0));
                bitmap.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
            }
        }
    }


    public bool IsReusable {
        get {
            return false;
        }
    }


}

2.在aspx中调用Session中存储的验证码

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;

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

    }
    protected void Button1_Click(object sender, EventArgs e)
    {
        string yzm = Convert.ToString(Session ["Code"]);
        Response.Write(yzm);
        if (yzm==TextBox1 .Text )
        {
            Response.Write("验证码正确");
        }
        else
        {
            Response.Write("验证码不正确，请重新输入");
            TextBox1.Text = "";
        }
    }
}

摘自编程爱好者

补充：Web开发 , ASP.Net ,