DeflateStream CopyTo writes nothing and throws no exceptions

问题

I've basically copied this code sample directly from msdn with some minimal changes. The CopyTo method is silently failing and I have no idea why. What would cause this behavior? It is being passed a 78 KB zipped folder with a single text file inside of it. The returned FileInfo object points to a 0 KB file. No exceptions are thrown.

    public static FileInfo DecompressFile(FileInfo fi)
    {
        // Get the stream of the source file.
        using (FileStream inFile = fi.OpenRead())
        {
            // Get original file extension, 
            // for example "doc" from report.doc.cmp.
            string curFile = fi.FullName;
            string origName = curFile.Remove(curFile.Length
                    - fi.Extension.Length);

            //Create the decompressed file.
            using (FileStream outFile = File.Create(origName))
            {
                // work around for incompatible compression formats found
                // here http://george.chiramattel.com/blog/2007/09/deflatestream-block-length-does-not-match.html
                inFile.ReadByte();
                inFile.ReadByte();

                using (DeflateStream Decompress = new DeflateStream(inFile,
                    CompressionMode.Decompress))
                {
                    // Copy the decompression stream 
                    // into the output file.
                    Decompress.CopyTo(outFile);

                    return new FileInfo(origName);
                }
            }
        }
    }

回答1:

In a comment you say that you are trying to decompress a zip file. The DeflateStream class can not be used like this on a zip file. The MSDN example you mentioned uses DeflateStream to create individual compressed files and then uncompresses them.

Although zip files might use the same algorithm (not sure about that) they are not just compressed versions of a single file. A zip file is a container that can hold many files and/or folders.

If you can use .NET Framework 4.5 I would suggest to use the new ZipFile or ZipArchive class. If you must use an earlier framework version there are free libraries you can use (like DotNetZip or SharpZipLib).

来源：https://stackoverflow.com/questions/19165884/deflatestream-copyto-writes-nothing-and-throws-no-exceptions

标签

.net

compression

zip