metro压缩和解压文件

在1.zip中增加一张新图片
StorageFile jpg = await KnownFolders.PicturesLibrary.GetFileAsync("1.jpg");
            StorageFile zip = await KnownFolders.PicturesLibrary.GetFileAsync("1.zip");

            //把上面这句改成如下就成了压缩文件
            //StorageFile zip = await KnownFolders.PicturesLibrary.CreateFileAsync(jpg.DisplayName+".zip",CreationCollisionOption.ReplaceExisting);
　　
　　
            using (ZipArchive archive = new ZipArchive((await zip.OpenAsync(FileAccessMode.ReadWrite)).AsStream(), ZipArchiveMode.Update))
            {
                ZipArchiveEntry readmeEntry = archive.CreateEntry(jpg.Name);
                byte[] buffer = WindowsRuntimeBufferExtensions.ToArray(await FileIO.ReadBufferAsync(jpg));
                using (var writer = readmeEntry.Open())
                {
                    await writer.WriteAsync(buffer, 0, buffer.Length);
                }
            }

 
把1.jpg从1.zip中删除
StorageFile zip = await KnownFolders.PicturesLibrary.GetFileAsync("1.zip");
            using (ZipArchive archive = new ZipArchive((await zip.OpenAsync(FileAccessMode.ReadWrite)).AsStream(), ZipArchiveMode.Update))
            {
                //删除文件
                archive.GetEntry("1.jpg").Delete();
            }

//导出1.jpg,newFile为要到出的文件

StorageFile zip = await KnownFolders.PicturesLibrary.GetFileAsync("1.zip");
            using (ZipArchive archive = new ZipArchive((await zip.OpenAsync(FileAccessMode.ReadWrite)).AsStream(), ZipArchiveMode.Update))
            {
　　　　　　　　　　　　ZipArchiveEntry zipArchiveEntry = archive.GetEntry("1.jpg").
　　　　　　　　　　　　using (Stream fileData = zipArchiveEntry.Open())
                            {
                                StorageFile newFile = await KnownFolders.PicturesLibrary.CreateFileAsync(zipArchiveEntry.FullName, CreationCollisionOption.ReplaceExisting);
                                using (IRandomAccessStream newFileStream = await newFile.OpenAsync(FileAccessMode.ReadWrite))
                                {
                                    using (Stream s = newFileStream.AsStreamForWrite())
                                    {
                                        await fileData.CopyToAsync(s);
                                        await s.FlushAsync();
                                    }
                                }
                            }


　　　　　　}