validatecodecontrol.ascx.cs

ASP.NET 2.0动态网站设计实例源代码,本书介绍了ASP.NET2.0的基础知识

using System;
using System.Drawing;
using System.Web;

public partial class Admin_ValidateCodeControl : System.Web.UI.UserControl
{
 protected void Page_Load(object sender, EventArgs e)
 {
  this.CreateCheckCodeImage(GenerateCheckCode(5, false));
 }
 /// <summary>
 /// 随机生成字符串
 /// </summary>
 /// <param name="codeCount">字符串个数</param>
 /// <param name="isSaveCookies">是存入COOKIES中,否则存入SESSION中</param>
 /// <returns></returns>
 private string GenerateCheckCode(int codeCount, bool isSaveCookies)
 {
  int number;
  char code;
  string checkCode = String.Empty;

  System.Random random = new Random();

  for (int i = 0; i < codeCount; i++)
  {
   number = random.Next();

   if (number % 2 == 0)
    code = (char)('0' + (char)(number % 10));
   else
    code = (char)('A' + (char)(number % 26));

   checkCode += code.ToString();
  }

  if (isSaveCookies)
  {
   Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));
  }
  else
  {
   Page.Session.Contents["CheckCode"] = checkCode;
  }


  return checkCode;
 }

 /// <summary>
 /// 生成图片
 /// </summary>
 /// <param name="checkCode"></param>
 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();
  }
 }
}