asp.net 压缩解压缩zip文件

[csharp] using System; 
using System.IO; 
using System.Diagnostics; 
using Microsoft.Win32; 
 
using ICSharpCode.SharpZipLib.Checksums; 
using ICSharpCode.SharpZipLib.Zip; 
 
///压缩、解压缩类 
namespace DotNet.Utilities 
{ 
    public class SharpZip 
    { 
        public SharpZip() 
        { } 
 
        /// <summary> 
        /// 压缩 
        /// </summary>  
        /// <param name="filename"> 压缩后的文件名(包含物理路径)</param> 
        /// <param name="directory">待压缩的文件夹(包含物理路径)</param> 
        public static void PackFiles(string filename, string directory) 
        { 
            try 
            { 
                FastZip fz = new FastZip(); 
                fz.CreateEmptyDirectories = true; 
                fz.CreateZip(filename, directory, true, ""); 
                fz = null; 
            } 
            catch (Exception) 
            { 
                throw; 
            } 
        } 
 
        /// <summary> 
        /// 解压缩 
        /// </summary> 
        /// <param name="file">待解压文件名(包含物理路径)</param> 
        /// <param name="dir"> 解压到哪个目录中(包含物理路径)</param> 
        public static bool UnpackFiles(string file, string dir)