ASP.NET中图片显示方法实例

2019-12-19 11:52冰封的心 ASP.NET教程

这篇文章主要介绍了ASP.NET中图片显示方法,实例分析了ASP.NET图片显示所涉及的图片路径、缩略图及更新数据库图片浏览次数等相关技巧,需要的朋友可以参考下

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：

复制代码代码如下:

<%@ WebHandler Language="C#" Class="netpix.ImageGenerator" %>

genimage.ashx.cs：

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									// Copyright (C) 2003 by Greg Ennis

									// (mailto:greg@ennis.net)

									//

									// 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);

									      }

									    }

									  }

									}