C# asp.net 解压缩

#region 解压实现

        /// <summary>
        /// 功能：解压zip格式的文件。
        /// </summary>
        /// <param name="zipFilePath">压缩文件路径</param>
        /// <param name="unZipDir">解压文件存放路径,为空时默认与压缩文件同一级目录下，跟压缩文件同名的文件夹</param>
        /// <param name="err">出错信息</param>
        /// <returns>解压是否成功</returns>
        public static string UnZipFile(string zipFilePath, string unZipDir, out string err)
        {
            err = "";
            if (zipFilePath == string.Empty)
            {
                err = "压缩文件不能为空！";
                return err;
            }
            if (!File.Exists(zipFilePath))
            {
                err = "压缩文件不存在！";
                return err;
            }
            //解压文件夹为空时默认与压缩文件同一级目录下，跟压缩文件同名的文件夹
            if (unZipDir == string.Empty)
                unZipDir = zipFilePath.Replace(Path.GetFileName(zipFilePath), Path.GetFileNameWithoutExtension(zipFilePath));
            if (!unZipDir.EndsWith("//"))
                unZipDir += "//";
            if (!Directory.Exists(unZipDir))
                Directory.CreateDirectory(unZipDir);

            try
            {
                using (ZipInputStream s = new ZipInputStream(File.OpenRead(zipFilePath)))
                {
                    ZipEntry theEntry;
                    while ((theEntry = s.GetNextEntry()) != null)
                    {
                        string directoryName = Path.GetDirectoryName(theEntry.Name);
                        string fileName = Path.GetFileName(theEntry.Name);
                        if (directoryName.Length > 0)
                        {
                            Directory.CreateDirectory(unZipDir + directoryName);
                        }
                        if (!directoryName.EndsWith("//"))
                            directoryName += "//";
                        if (fileName != String.Empty)
                        {
                            using (FileStream streamWriter = File.Create(unZipDir + theEntry.Name))
                            {

                                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;
                                    }
                                }
                            }
                        }
                    }//while
                }
            }
            catch (Exception ex)
            {
                err = ex.Message;
                return "上传失败";
            }
            return "上传成功";
        }
        //解压结束
        #endregion 解压实现

ICSharpCode.SharpZipLib.dll下载并引用。结合以上代码可实现zip压缩包解压。