如何使用ICSharpCode.SharpZipLib.Zip压缩存储在MemoryStream中的Word文档？

Question

我正在尝试压缩存储在MemoryStream中的Word文档，如下所示：

MemoryStream outputMemStream = new MemoryStream();
ZipOutputStream zipStream = new ZipOutputStream(outputMemStream);

zipStream.SetLevel(3); //0-9, 9 being the highest level of compression

ZipEntry newEntry = new ZipEntry("my_document.docx");
newEntry.DateTime = DateTime.Now;
zipStream.PutNextEntry(newEntry);

//docMS is a MemoryStream that contains a Word document
StreamUtils.Copy(docMS, zipStream, new byte[4096]);
docMS.Close();
zipStream.CloseEntry();

zipStream.IsStreamOwner = false;    // False stops the Close also Closing the underlying stream.
zipStream.Close();      // Must finish the ZipOutputStream before using outputMemStream.

outputMemStream.Position = 0;

context.Response.AddHeader("content-disposition", String.Format("attachment;filename={0}", "my_document.zip"));
context.Response.ContentType = "application/octet-stream";
zipStream.WriteTo(context.Response.OutputStream);
context.Response.End();

下载并解压缩zip文件后，“my_document.docx”将打开为空白文档。如果我修改上面的代码，以便通过MemoryStream“docMS”直接下载（而不是压缩）'my_document.docx'文件，那么文档就可以正常打开。我无法弄清楚原因。