ASP.NET中图片显示方法实例

2024-07-10 13:29:15

字体：大中小

来源：转载

供稿：网友

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：

// 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);

      }

    }

  }

}