需要SharpZipLib引用，ASP.NET 在线压缩与在线解压缩源码:

using System; using System.IO; using ICSharpCode.SharpZipLib.Checksums; using ICSharpCode.SharpZipLib.Zip; using ICSharpCode.SharpZipLib.Zip.Compression; using ICSharpCode.SharpZipLib.Zip.Compression.Streams; /// 
 /// 2005-7-9 /// 垃圾猪 /// ewebapp.net /// 
 namespace eWebapp.Upload {     /// 
     /// 压缩解压处理。     /// 
     public class eZip     {         #region 私有域         private string zipname = string.Empty;         private string password = string.Empty;         private int level = 9;         private string unzipdir = string.Empty;         private Crc32 crc;         ZipOutputStream s;         #endregion         #region 属性         /// 
         /// 压缩文件名称         /// 
         public string Zipname         {             set{ zipname = value;}         }         /// 
         /// 解压文件夹         /// 
         public string Unzipdir         {             set { unzipdir = value;}         }         /// 
         /// 压缩文件密码         /// 
         public string Password         {             set {password = value;}         }         /// 
         /// 压缩级别         /// 
         public int Level         {             set {level = value;}         }         public eZip()         {             //             // TODO: 在此处添加构造函数逻辑             //         }         #endregion         /// 
         /// 创建压缩文件         /// 
         public void CreateZip()         {             crc = new Crc32();             s = new ZipOutputStream(File.Create(this.zipname));             s.SetLevel(level);             s.Password = password;         }         /// 
         /// 结束操作         /// 
         public void FinishZip()         {             s.Finish();             s.Close();         }         /// 
         /// 增加一个文件         /// 
         ///          ///          ///          ///          ///          private void addFile(Crc32 _crc,ZipOutputStream _s,string _filename,long _filesize,byte[] _buffer)         {             // 添加一个文件到压缩文件中             ZipEntry entry = new ZipEntry(_filename);                          entry.DateTime = DateTime.Now;             entry.Size = _filesize;                          _crc.Reset();             _crc.Update(_buffer);                          entry.Crc  = _crc.Value;                          _s.PutNextEntry(entry);                          _s.Write(_buffer, 0, _buffer.Length);         }         /// 
         /// 添加一个文件到压缩文件中         /// 
         ///          public void AddFile(string _filename)         {             FileStream fs = File.OpenRead(_filename);             byte[] buffer = new byte[fs.Length];             fs.Read(buffer, 0, buffer.Length);             string filename = System.IO.Path.GetFileName(_filename);             long m_fLength = fs.Length;             fs.Close();             addFile(this.crc,this.s,filename,m_fLength,buffer);         }         /// 
         /// 新建文本文件         /// 
         ///          ///          ///          ///          private void addText(Crc32 _crc,ZipOutputStream _s,string _filename,string _text)         {             byte[] text = System.Text.Encoding.Default.GetBytes(_text);             addFile(_crc,_s,_filename,text.Length,text);         }         /// 
         /// 添加一个指定内容的文本文件到压缩文件中         /// 
         ///          ///          public void AddText(string _filename,string _text)         {             addText(this.crc,this.s,_filename,_text);         }         /// 
         /// 解压处理         /// 
         public void Unzip()         {                                  string unzipdirectoryroot = this.unzipdir;                                       // 调用组件中读取压缩文件的对象             ZipInputStream s = new ZipInputStream(File.OpenRead(this.zipname));             s.Password = this.password;             ZipEntry theEntry;                          while ((theEntry = s.GetNextEntry()) != null)             {                 // 当前解压到的目录，Path.GetDirectoryName(theEntry.Name)为提取压缩文件目录                 string directoryName = Path.Combine(unzipdirectoryroot,Path.GetDirectoryName(theEntry.Name));                 // 当前正在解压的文件                 string fileName = Path.Combine(directoryName,Path.GetFileName(theEntry.Name));                 // 创建目录                 Directory.CreateDirectory(directoryName);                 if (fileName != String.Empty)                  {                     try                     {                         // 创建解压文件                         FileStream streamWriter = File.Create(fileName);                         // 将数据写入文件                         int size = 2048;                         byte[] data = new byte[2048];                         while (true)                          {                             size = s.Read(data, 0, data.Length);                             if (size > 0)                              {                                 streamWriter.Write(data, 0, size);                             }                              else                              {                                 break;                             }                         }                                          streamWriter.Close();                     }                     catch                     {                     }                                      }             }             s.Close();         }     } }