asp.net解压缩文件夹

需要用到第三方控件ICSharpCode.SharpZipLib.dll
using System.IO;
using System.IO.Compression;
using ICSharpCode.SharpZipLib.Zip;
using ICSharpCode.SharpZipLib.GZip;
using ICSharpCode.SharpZipLib.Checksums;  
  #region 压缩文件夹,支持递归
/// <summary>
        ///　压缩文件夹
        /// </summary>
        /// <param name="dir">待压缩的文件夹</param>
        /// <param name="targetFileName">压缩后文件路径（包括文件名）</param>
        /// <param name="recursive">是否递归压缩</param>
        /// <returns></returns>
        public bool Compress(string dir, string targetFileName, bool recursive)
        {
            //如果已经存在目标文件，询问用户是否覆盖
            if (File.Exists(targetFileName))
            {
               // if (!_ProcessOverwrite(targetFileName))
                    return false;
            }
            string[] ars = new string[2];
            if (recursive == false)
            {
                //return Compress(dir, targetFileName);
   &nb