无法压缩解压缩

Question

我正在尝试通过从WP8文件中读取内容来压缩和解压缩数据。.I无法压缩或decompress.While压缩生成的字符串始终为空。在解压缩时出现错误，因为“在SYSTEM.IO.COMPRESSION.NI.DLL中发生了'System.IO.InvalidDataException‘类型的异常，但在用户代码中没有处理

附加信息:块长度与其补码不匹配。“

代码如下

   public static async void CompressDecompress()
    {
        //Location of File to be Compressed
        string toCompressFileName = "ms-appx:///Assets/data.txt";  

        StorageFile toCompressFile = await StorageFile.GetFileFromApplicationUriAsync(new Uri(toCompressFileName));
        Stream toCompressStream = await toCompressFile.OpenStreamForReadAsync();
        toCompressStream.Position = 0;

        string compressedString = Compress(toCompressStream);

        //Location of File to be Decompressed
        string toDecompressFileName = "ms-appx:///Assets/zipped_data.txt";
        StorageFile toDecompressFile = await StorageFile.GetFileFromApplicationUriAsync(new Uri(toDecompressFileName));
        Stream toDecompressStream = await toDecompressFile.OpenStreamForReadAsync();
        toDecompressStream.Position = 0;

        string decompressedString = DeCompress(toDecompressStream);

    }

    public static string Compress(Stream toCompressStream)
    {
        using (MemoryStream resultCompressedStream = new MemoryStream())
        {
            using (DeflateStream compressionStream = new DeflateStream(resultCompressedStream, CompressionMode.Compress))
            {
                toCompressStream.CopyTo(compressionStream);
                toCompressStream.Flush();

                return Encoding.UTF8.GetString(resultCompressedStream.ToArray(), 0, Convert.ToInt32(resultCompressedStream.Length));
            }
        }
    }

    public static string DeCompress(Stream toDecompressStream)
    {
        using (MemoryStream resultDeCompressedStream = new MemoryStream())
        {
            using (DeflateStream decompressionStream = new DeflateStream(toDecompressStream, CompressionMode.Decompress))
            {
                decompressionStream.CopyTo(resultDeCompressedStream);
                decompressionStream.Flush();

                return Encoding.UTF8.GetString(resultDeCompressedStream.ToArray(), 0, Convert.ToInt32(resultDeCompressedStream.Length));
            }
        }           
    }

请帮我找出哪里出了问题。

Answer 1

如果没有一个好的Minimal, Complete, and Verifiable example的问题，很难说所有的问题都可能是错的。但可以肯定的是，您应该从压缩流中读取数据，而不是写入数据。例如，就像这样：

   using (MemoryStream resultDeCompressedStream = new MemoryStream())
   {
       using (DeflateStream decompressionStream = new DeflateStream(decompressfileStream, CompressionMode.Decompress))
       {
           decompressionStream.CopyTo(resultDeCompressedStream);

           string decompressedString = Encoding.UTF8.GetString(resultDeCompressedStream.ToArray(), 0, Convert.ToInt32(resultDeCompressedStream.Length));
       }
   }

注意：您的代码还使用了datafileStream对象，该对象当然只是原始的未压缩数据文件，并且已经被读取到最后。因此，即使忽略了您滥用DeflateStream的事实，这也不会起作用。我在上面的示例中也解决了这个问题，即通过写入明显的预期输出流，并使用decompressfileStream对象作为DeflateStream的输入。

注意：从你的问题中还不清楚你是否也有压缩方面的问题。但是如果是这样的话，我建议您在复制数据之后显式地刷新/关闭DeflateStream对象。