using?System;
using?System.Drawing;
using?System.Drawing.Drawing2D;
using?System.Drawing.Imaging;
using?System.IO;
using?System.Web;
using?System.Web.UI;

public?partial?class?CheckCode?:?Page
{
????protected?void?Page_Load（object?sender?EventArgs?e）
????{
????????CreateCheckCodeImage（GenerateCheckCode（））;
????}

????private?string?GenerateCheckCode（）
????{
????????int?number;
????????char?code;
????????string?checkCode?=?String.Empty;

????????Random?random?=?new?Random（）;

????????for?（int?i?=?0;?i?????????{
????????????number?=?random.Next（）;
????????????code?=?（char）?（‘0‘?+?（char）?（number%10））;
????????????checkCode?+=?code.ToString（）;
????????}
????????Response.Cookies.Add（new?HttpCookie（“CheckCode“?checkCode））;
????????return?checkCode;
????}

????private?void?CreateCheckCodeImage（string?checkCode）
????{
????????if?（String.IsNullOrEmpty（checkCode））
????????{
????????????return;
????????}
????????Bitmap?bitmap?=?new?Bitmap（（int）?Math.Ceiling（（checkCode.Length*12.5））?22）;
????????Graphics?graphics?=?Graphics.FromImage（bitmap）;
????????try
????????{
????????????//?生成隨機生成器
????????????Random?random?=?new?Random（）;

????????????//?清空圖片背景色
????????????graphics.Clear（Color.White）;

????????????//?畫圖片的背景噪音線
????????????for?（int?i?=?0;?i?????????????{
????????????????int?x1?=?random.Next（bitmap.Width）;
????????????????int?x2?=?random.Next（bitmap.Width）;
????????????????int?y1?=?random.Next（bitmap.Height）;
????????????????int?y2?=?random.Next（bitmap.Height）;
????????????????graphics.DrawLine（new?Pen（Color.Black）?x1?y1?x2?y2）;
????????????}

????????????Font?font?=?new?Font（“Arial“?12?（Fontstyle.Bold））;
????????????LinearGradientBrush?brush?=?new?LinearGradientBrush（new?Rectangle（0?0?bitmap.Width?bitmap.Height）
????????????????????????????????????????????????????????????????Color.Blue?Color.DarkRed?1.2f?true）;
????????????graphics.DrawString（checkCode?font?brush?2?2）;

????????????//?畫圖片的前景噪音點
????????????for?（int?i?=?0;?i?????????????{
????????????????int?x?=?random.Next（bitmap.Width）;
????????????????int?y?=?random.Next（bitmap.Height）;
????????????????bitmap.SetPixel（x?y?Color.FromArgb（random.Next（）））;
????????????}

????????????//?畫圖片的邊框線
????????????graphics.DrawRectangle（new?Pen（Color.Silver）?0?0?bitmap.Width?-?1?bitmap.Height?-?1）;
????????????MemoryStream?ms?=?new?MemoryStream（）;
????????????bitmap.Save（ms?ImageFormat.Gif）;
????????????Response.ClearContent（）;
????????????Response.ContentType?=?“image/Gif“;
????????????Response.BinaryWrite（ms.ToArray（））;
????????}
????????finally
????????{
????????????graphics.Dispose（）;
????????????bitmap.Dispose（）;
????????}
????}
}