using?System;
using?System.Drawing;
using?System.Drawing.Imaging;
using?System.Text;
using?System.Web;
using?System.Web.SessionState;

namespace?HttpModuleDemo
{
????///?<summary>
????///?VerificationCode?的摘要說明
????///?</summary>
????public?class?VerificationCode?:?IHttpHandler,IRequiresSessionState?
????{
????????public?void?ProcessRequest(HttpContext?context)
????????{
????????????context.Response.ContentType?=?"image/jpeg";
????????????//建立Bitmap對象，繪圖
????????????//Bitmap:是用于處理由像素數據定義的圖像的對象
????????????Bitmap?bitmap?=?new?Bitmap(200,60);
????????????//Graphics:封裝一個?GDI+?繪圖圖面
????????????Graphics?graph?=?Graphics.FromImage(bitmap);
????????????graph.FillRectangle(new?SolidBrush(Color.White),?0,?0,?200,?60);
????????????Font?font?=?new?Font(FontFamily.GenericSerif,?48,?FontStyle.Bold,?GraphicsUnit.Pixel);
????????????Random?r?=?new?Random();
????????????string?letters?=?"ABCDEFGHIJKLMNPQRSTUVWXYZ";
????????????string?letter;
????????????StringBuilder?s?=?new?StringBuilder();
????????????
????????????//添加隨機的五個字母
????????????for?(int?x?=?0;?x?<?5;?x++)
????????????{
????????????????letter?=?letters.Substring(r.Next(0,?letters.Length?-?1),?1);
????????????????s.Append(letter);
????????????????graph.DrawString(letter,?font,?new?SolidBrush(Color.Black),?x?*?38,?r.Next(0,?15));
????????????}
????????????/*
????????????//混淆背景
????????????Pen?linePen?=?new?Pen(new?SolidBrush(Color.Black),?2);
????????????for?(int?x?=?0;?x?<?6;?x++)
????????????????graph.DrawLine(linePen,?new?Point(r.Next(0,?199),?r.Next(0,?59)),?new?Point(r.Next(0,?199),?r.Next(0,?59)));
????????????*/
????????????//將圖片保存到輸出流中??????
????????????bitmap.Save(context.Response.OutputStream,?ImageFormat.Jpeg);

????????????////如果沒有實現IRequiresSessionState，則這里會出錯，也無法生成圖片
????????????context.Session["CheckCode"]?=?s.ToString();
????????????context.Response.End();???
????????}

????????public?bool?IsReusable
????????{
????????????get
????????????{
????????????????return?false;
????????????}
????????}
????}
}

?

轉載于:https://www.cnblogs.com/AngelLee2009/archive/2011/10/29/2228278.html

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