Zip file created directly from memorystream is empty and getting error "Cannot access a closed Stream" in C#

Question

I am trying to create a zip file with one text file and send as FileStreamResult.
The zip file is empty and getting error "Cannot access a closed Stream".

If I write the memorystream to byte array, I am getting text file inside zipped file.
But I wanted to avoid converting to byte array as it will take extra memory.

Is there a way to generate zip file without using ToArray() method?

Sample code below :

     return File(outStream, "application/zip", "MyFile.zip");
     ActionResult Index()
     {
         using var outStream = new MemoryStream();
         using (var archive = new System.IO.Compression.ZipArchive(outStream, System.IO.Compression.ZipArchiveMode.Create, true))
         {
            var fileInArchive = archive.CreateEntry("MyFile.txt", System.IO.Compression.CompressionLevel.Optimal);
            using var entryStream = fileInArchive.Open();
            using var fileToCompressStream = new MemoryStream(System.Text.Encoding.UTF8.GetBytes("HelloWorld"));
            fileToCompressStream.CopyTo(entryStream);
        }
        return File(outStream, "application/zip", "MyFile.zip");

    //var compressedBytes = outStream.ToArray();
    //return File(compressedBytes, "application/zip", "MyFile.zip");
}

Answer 1

Maybe you must remove the using for outStream and do this:

 . . .
 outStream.Position = 0;
 return File(outStream, "application/zip", "MyFile.zip");