[
  {
    "Id": "232323",
    "ThreadId": "68307",
    "Html": "<p>&nbsp;</p>\r\n<p>how far does this go to deturmine if the file is really a zip? can it catch the situation where someone takes a regular file and changes the extension to .zip? can it detect if the file has 0 bytes in it? the situation with 0 bytes was an issue with DynaZip i believe when it tried to extract. im trying to avoid the same problems. i see there is a test extract option. for really large files, is this process shortened somehow by canceling the extract or by another method?</p>",
    "PostedDate": "2009-09-08T10:52:14.42-07:00",
    "UserRole": null,
    "MarkedAsAnswerDate": null
  },
  {
    "Id": "232351",
    "ThreadId": "68307",
    "Html": "<p>To understand how IsZipFile() works, I suggest you <a href=\"http://cheeso.members.winisp.net/DotNetZipHelp/html/2467cbed-488a-e0e1-2a66-9c49e9edbf26.htm\">Read the doc</a>.&nbsp;</p>\r\n<p>A zero byte file is not a zipfile and this method will indicate as much.&nbsp;&nbsp;</p>\r\n<p>a regular file with the extension changed is also not a zipfile and IsZipFile() will again return False.</p>\r\n<p>This is easy for you to test.</p>\r\n<p>The text extract actually extracts the files into a null stream.&nbsp; The process is shortened because the output files are not written to a filesystem, so there is no IO.&nbsp; But, all the decompression happens, and the checksum verification happens.&nbsp; This can take some time for large files, even without the IO.&nbsp;&nbsp; This does not work with an encrypted zip file.&nbsp; If you want to&nbsp;verify an encrypted zip file, you will have to do it on your own.</p>\r\n<p>&nbsp;</p>",
    "PostedDate": "2009-09-08T12:16:23.183-07:00",
    "UserRole": null,
    "MarkedAsAnswerDate": null
  },
  {
    "Id": "232413",
    "ThreadId": "68307",
    "Html": "<p>if you read the previous before i edited disregard. ill retest the same case</p>",
    "PostedDate": "2009-09-08T14:39:18.077-07:00",
    "UserRole": null,
    "MarkedAsAnswerDate": null
  }
]