生成验证码图片

Code

   
     using System;
using System.Data;
using System.Configuration;
using System.Collections;
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;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;

namespace WebApplication4
{
 public partial class login : System.Web.UI.Page
 {
 protected void Page_Load(object sender, EventArgs e)
 {
 Response.Clear();
 Random r = new Random((int)DateTime.Now.Ticks);
 int number = r.Next(1000, 9999);
 Session["validateCode"] = number;

 Bitmap bmp = new Bitmap(50, 25);
 Graphics g = Graphics.FromImage(bmp);
 HatchBrush hb = new HatchBrush(HatchStyle.Cross, Color.Green, Color.White);

 g.FillRectangle(hb, 0, 0, 25, 50);
 g.DrawString(number.ToString(), new Font("arial", 14), new SolidBrush(Color.Red), 0, 0);
 bmp.Save(Response.OutputStream, ImageFormat.Jpeg);
 hb.Dispose();
 g.Dispose();
 bmp.Dispose();
 Response.Flush();
 }
 }
}