如何自动生成缩略图？(事先没有缩略图)

Question

.net的高手们帮帮拉！不胜感激。..

Answer 1

Stream stream=File1.PostedFile.InputStream;
if (stream!=null)
{
Bitmap bitmap=new System.Drawing.Bitmap(stream);
System.Drawing.Image image=bitmap.GetThumbnailImage(10,10,null,null);
image.Save("c://image//aa.gif",System.Drawing.Imaging.ImageFormat.Gif);
}

Answer 2

敢问blackcatiii(ljh):用asp行么？

Answer 3

no.
asp的话就得要自己写组件了。

Answer 4

2002软件报上已刊过（asp.net），C＃提供了缩略方法。

Answer 5

欧？可有组件共享？(to  blackcatiii(ljh) );
give me "2002软件报上已刊过（asp.net），C＃提供了缩略方法。"
my email:[email protected]

Answer 6

sample:
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Imaging;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.IO;namespace DayOfDeveloper
{
    public class ThumbnailGenerator : System.Web.UI.Page
    {
        private void Page_Load(object sender, System.EventArgs e)
        {
            String _path = Server.MapPath("images/");
            if ( !_path.EndsWith(@"\") )
                _path += @"\";            DirectoryInfo _di = new DirectoryInfo(_path);
            FileInfo[] _fi = _di.GetFiles("*.jpg");            foreach ( FileInfo _f in  _fi)
            {
                if ( !_f.Name.StartsWith("thumb_") )
                {
                    String _imgName = _f.Name;
            
                    System.Drawing.Image _img = System.Drawing.Image.FromFile(_path + _imgName);                    if ( _img.Height > 72 )
                    {
                        Int32 _height = _img.Height;
                        Int32 _width = _img.Width;
            
                        Bitmap _imgOutput;
                        Double _dif;                        _dif = Convert.ToDouble(Decimal.Divide(_width,_height));
                        _width = Convert.ToInt32(Math.Ceiling(72 * _dif));
                        _imgOutput = new Bitmap(_img, _width, 72);
                        _img.Dispose();                        try
                        {
                            _imgOutput.Save(_path + "thumb_" + _imgName.ToLower(), System.Drawing.Imaging.ImageFormat.Jpeg);
                            _imgOutput.Dispose();
                            Response.Write("thumb_" + _imgName.ToLower() + " Saved</b><br>");
                        }
                        catch ( Exception _ex )
                        {
                            Response.Write("<b>Error Saving File</b><br>");
                            Response.Write(_ex.Message);
                            Response.Write("<br>");
                            Response.Write(_ex.StackTrace);
                            Response.Write("<br>");
                        }
                    }
                }
            }
        }        #region Web Form Designer generated code
        override protected void OnInit(EventArgs e)
        {
            //
            // CODEGEN: This call is required by the ASP.NET Web Form Designer.
            //
            InitializeComponent();
            base.OnInit(e);
        }
        
        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent()
        {    
            this.Load += new System.EventHandler(this.Page_Load);
        }
        #endregion
    }
}

Answer 7

Image类里有一个GetThumbnailImage方法

Answer 8

像这样？
http://www.aspsky.net/article/list.asp?id=2576
http://www.aspsky.net/article/list.asp?id=2575
http://www.aspsky.net/article/list.asp?id=2573
http://www.aspsky.net/article/list.asp?id=2574
可以？