Develop windows app like OneDrive app in windows 8.1

Question

The OneDrive app in Windows 8.1, can let user choose "Make available offline" or "Make available online-only".

When user choose "Make available online-only", user still can see the data in windows file explorer, but the data not really store in local disk. When user double click the data, OneDrive will download data from cloud to local, if computer doesn't have net, user can't open data.

Have any way to display data in windows file explorer even the data is not store in local disk...I can't find any solution or API can let me use...

Answer 1

Though Windows itself may not support it the same way with built-in handling, you should still be able to code up a solution similar to what you were looking for. From what I can tell the "smart files" that OneDrive/SkyDrive were using could also be called "Placeholder Files" now. They're basically just NTFS Reparse Points with a custom Reparse Tag Identifier associated to the file types.

See here: Reparse Points

It should be noted however since it was mentioned above, that even though the old Reparse Tag identifier was deprecated, they seem to be re-implementing a version of the Placeholder files for Windows 10. Recent builds included new "ONEDRIVE" reparse tag identifiers.

See here: new Reparse Tags (twitter)