首先要引用一下類庫：using Ionic.Zip;這個類庫可以到網上下載。

  下面對類庫使用的封裝方法：

             /// <summary>
            /// 得到指定的輸入流的ZIP壓縮流對象【原有流對象不會改變】
            /// </summary>
            /// <param name="sourceStream"></param>
            /// <returns></returns>
            public static Stream ZipComPRess(Stream sourceStream, string entryName = "zip")
            {
                MemoryStream compressedStream = new MemoryStream();
                if (sourceStream != null)
                {
                    long sourceOldPosition = 0;
                    try
                    {
                        sourceOldPosition = sourceStream.Position;
                        sourceStream.Position = 0;
                        using (ZipFile zip = new ZipFile())
                        {
                            zip.AddEntry(entryName, sourceStream);
                            zip.Save(compressedStream);
                            compressedStream.Position = 0;
                        }
                    }
                    catch
                    {
                    }
                    finally
                    {
                        try
                        {
                            sourceStream.Position = sourceOldPosition;
                        }
                        catch
                        {
                        }
                    }
                }
                return compressedStream;
            }

            /// <summary>
            /// 得到指定的字節數組的ZIP解壓流對象
            /// 當前方法僅適用于只有一個壓縮文件的壓縮包，即方法內只取壓縮包中的第一個壓縮文件
            /// </summary>
            /// <param name="sourceStream"></param>
            /// <returns></returns>
            public static Stream ZipDecompress(byte[] data)
            {
                Stream decompressedStream = new MemoryStream();
                if (data != null)
                {
                    try
                    {
                        MemoryStream dataStream = new MemoryStream(data);
                        using (ZipFile zip = ZipFile.Read(dataStream))
                        {
                            if (zip.Entries.Count > 0)
                            {
                                zip.Entries.First().Extract(decompressedStream);
                                // Extract方法中會操作ms，后續使用時必須先將Stream位置歸零，否則會導致后續讀取不到任何數據
                                // 返回該Stream對象之前進行一次位置歸零動作
                                decompressedStream.Position = 0;
                            }
                        }
                    }
                    catch
                    {
                    }
                }
                return decompressedStream;
            }
            /// <summary>
            /// 壓縮ZIP文件
            /// 支持多文件和多目錄，或是多文件和多目錄一起壓縮
            /// </summary>
            /// <param name="list">待壓縮的文件或目錄集合</param>
            /// <param name="strZipName">壓縮后的文件名</param>
            /// <param name="IsDirStruct">是否按目錄結構壓縮</param>
            /// <returns>成功：true/失敗：false</returns>
            public static bool CompressMulti(List<string> list, string strZipName, bool IsDirStruct)
            {
                try
                {
                    using (ZipFile zip = new ZipFile(Encoding.Default))//設置編碼，解決壓縮文件時中文亂碼
                    {
                        foreach (string path in list)
                        {
                            string fileName = Path.GetFileName(path);//取目錄名稱
                            //如果是目錄
                            if (Directory.Exists(path))
                            {
                                if (IsDirStruct)//按目錄結構壓縮
                                {
                                    zip.AddDirectory(path, fileName);
                                }
                                else//目錄下的文件都壓縮到Zip的根目錄
                                {
                                    zip.AddDirectory(path);
                                }
                            }
                            if (File.Exists(path))//如果是文件
                            {
                                zip.AddFile(path,"imges");
                            }
                        }
                        zip.Save(strZipName);//壓縮
                        return true;
                    }
                }
                catch (Exception)
                {
                    return false;
                }
            }
            /// <summary>
            /// 解壓ZIP文件
            /// </summary>
            /// <param name="strZipPath">待解壓的ZIP文件</param>
            /// <param name="strUnZipPath">解壓的目錄</param>
            /// <param name="overWrite">是否覆蓋</param>
            /// <returns>成功：true/失敗：false</returns>
            public static bool Decompression(string strZipPath, string strUnZipPath, bool overWrite)
            {
                try
                {
                    ReadOptions options = new ReadOptions();
                    options.Encoding = Encoding.Default;//設置編碼，解決解壓文件時中文亂碼
                    using (ZipFile zip = ZipFile.Read(strZipPath, options))
                    {
                        foreach (ZipEntry entry in zip)
                        {
                            if (string.IsNullOrEmpty(strUnZipPath))
                            {
                                strUnZipPath = strZipPath.Split('.').First();
                            }
                            if (overWrite)
                            {
                                entry.Extract(strUnZipPath, ExtractExistingFileAction.OverwriteSilently);//解壓文件，如果已存在就覆蓋
                            }
                            else
                            {
                                entry.Extract(strUnZipPath, ExtractExistingFileAction.DoNotOverwrite);//解壓文件，如果已存在不覆蓋
                            }
                        }
                        return true;
                    }
                }
                catch (Exception)
                {
                    return false;
                }
            }