ASP.NET中图片显示方法实例

本文实例讲述了asp.net中图片的显示方法。分享给大家供大家参考。具体如下：

genimage.ashx：

<%@ webhandler language="c#" class="netpix.imagegenerator" %>

genimage.ashx.cs：

// copyright (c) 2003 by greg ennis
// (mailto:[e-mail])
//
// the contents of this file are subject to the artistic license (the "license").
// you may not use this file except in compliance with the license. 
// you may obtain a copy of the license at:
// http://www.opensource.org/licenses/artistic-license.html
using system;
using system.collections;
using system.componentmodel;
using system.data;
using system.data.sqlclient;
using system.drawing;
using system.web;
using system.io;
using system.configuration;
using system.web.sessionstate;
using system.web.ui;
using system.web.ui.webcontrols;
using system.web.ui.htmlcontrols;
namespace netpix
{
  public class imagegenerator : ihttphandler 
  { 
    public bool isreusable 
    { get { return true; } } 
    public void processrequest(httpcontext context) 
    { 
      // get the image filename and album root path from the database
      //图片浏览次数
      int numviews;
      //图片数据库中的id
      int picid = convert.toint32(context.request["id"]);
      //图片路径　
      string imgpath = npdata.getpathtopicture(picid, out numviews);
      // writing an image to output stream
      context.response.contenttype = "image/jpg";
      // 'thumbnail' means we are requesting a thumbnail
      //显示缩略图
      if (context.request["thumbnail"] != null)
      {
        // need to load the image, resize it, and stream to the client.
        // calculate the scale so as not to stretch or distort the image.
        bitmap bmp = new bitmap(imgpath);
        float scale = 150.0f / system.math.max(bmp.height, bmp.width);
        system.drawing.image thumb = bmp.getthumbnailimage((int)(bmp.width * scale), (int)(bmp.height * scale), null, system.intptr.zero);
        thumb.save(context.response.outputstream, system.drawing.imaging.imageformat.jpeg);
        bmp.dispose();
        thumb.dispose();
      }
      else
      {
        // stream directly from the file
        // get the stream and send it out the response
        system.io.filestream fs = file.open(imgpath, filemode.open, fileaccess.read, fileshare.read);
        const int bytelength = 8192;
        byte[] bytes = new byte[bytelength];
        while( fs.read(bytes, 0, bytelength ) != 0 )
        {
          context.response.binarywrite(bytes); 
        }
        fs.close();
        //更新数据库浏览次数
        npdata.setnumviews(picid, numviews+1);
      }
    }
  }
}

使用方法：

imgctrl.imageurl = "genimage.ashx?id=" + request["id"];

希望本文所述对大家的asp.net程序设计有所帮助。