ASP.NET筆記之 Httphandler的操作詳解_實用技巧

1、httphandler

        

執行個體1：通過產生一張動態圖片輸出用戶端的IP地址、作業系統類型、瀏覽器類型

複製代碼 代碼如下:

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

using System;
using System.Web;

public class visitor : IHttpHandler {

    public void ProcessRequest(HttpContext context)
    {
        context.Response.ContentType = "image/JPEG";
        using (System.Drawing.Bitmap bitImage = new System.Drawing.Bitmap(330, 300))
        {
            //設定畫布
            using (System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitImage))
            {
                //IP
                g.DrawString("IP:" + context.Request.UserHostAddress, new System.Drawing.Font("宋體", 20), System.Drawing.Brushes.Red, new System.Drawing.PointF(0, 0));
                //作業系統
                g.DrawString("作業系統:" + context.Request.Browser.Platform, new System.Drawing.Font("宋體", 20), System.Drawing.Brushes.Red, new System.Drawing.PointF(0, 50));
                //瀏覽器
                g.DrawString("瀏覽器:" + context.Request.Browser.Type, new System.Drawing.Font("宋體", 20), System.Drawing.Brushes.Red, new System.Drawing.PointF(0, 100));
            }
            //儲存到輸出資料流中
            bitImage.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);

        }
    }

    public bool IsReusable {
        get {
            return false;
        }
    }

}

執行個體2：通過“下載”串連，彈出使用者附件儲存

html代碼：<a href="dowload.ashx">下載</a>

複製代碼 代碼如下:

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

using System;
using System.Web;

public class dowload : IHttpHandler {

    public void ProcessRequest(HttpContext context)
    {
        string fileName = HttpUtility.UrlEncode("悲劇.jpg");
        context.Response.ContentType = "image/JPEG";

        //開啟附件對話方塊  報文頭header和設定它的值
        context.Response.AddHeader("Content-Disposition", "attachment:filename=" + fileName);
        context.Response.WriteFile("蘋果.jpg");      
    }

    public bool IsReusable {
        get {
            return false;
        }
    }

}