The Windows 10 File Explorer has evolved slightly from its Windows 8 incarnation. Key among the new features is a Share button that lets you share files directly from your file system using the Share contract that also debuted in Windows 8, further evidence of the merging of the two previously separate desktop and Modern environments.
Note: File Explorer was called Windows Explorer in Windows 7 and older Windows versions.
As you may recall, Share is one of several contracts that arrived with Windows 8. These contracts provide formalized ways in which sandboxed Universal (Metro/Modern/Windows Store) apps can share information with each other. (Other contracts include Search, Settings, Play To, and App Picker.) As I noted in Windows 8 Feature Focus: Contracts, this OS feature is basically "copy and paste on steroids."
"Sandboxed apps cannot communicate with each other, by design," I wrote at the time. "So Microsoft has built system-level capabilities into Windows 8 that help overcome these limitations without subverting the security model. Additionally, these capabilities are rendered consistently from app to app, so that the user only needs to learn one method for searching, one method for sharing, and so on. These capabilities are known collectively as contracts."
Share is a contract in every sense of the word. If you initiate Share while viewing a web page in IE, for example, the Share pane that appears will list only those apps that can accept that type of share. If you do so from a different app, the list of possible apps could be different.
If you are familiar with the Share contract in Windows 8, you know that if you try to share from the desktop, you will be told that the desktop does not support sharing. That's because in Windows 8, the desktop was separated logically and technically from the Modern environment in which the new Universal apps run.
This is no longer true in Windows 10, however.
And while having a Share button in File Explorer isn't exactly earth shattering from a UI perspective, its presence there is in fact a big deal (though I don't actually expect a lot of people to use it). This says more about Windows 10—about the design of Windows 10—than almost anything I could write. The walls have come down.
To use Share, open File Explorer and navigate to a file, set of files, folder, or any combination of the above you wish to share. Then, open the Share pane in the ribbon. (You can do this whether you show or hide the ribbon by default.)
Select the items you wish to share and then click Share. When you do, a Windows 8-style Share pane appears. Only this time it actually works.
What you see in the pane will vary according to what items you've selected and which apps you have installed. For folders and/or documents, I see Fresh Paint (?), Mail and Windows Phone. For images, I also see Facebook and Twitter.
What this means, of course, is that users of traditional PCs can now use Universal apps somewhat seamlessly (though it's a bit weird to use a Modern interface on the desktop), and consistently with how this contract worked/works with other Universal apps. This will play a role in those apps being used more frequently in Windows 10.
For example, if you wanted to share photos with Facebook in Windows 8, you would almost certainly launch the Facebook app or web site and start from there. Alternatively, you could have used the OneDrive app (which inexplicably works with both OneDrive and the local file system) and share from there. But now in Windows 10, you can use the tool you actually use to manage photos—File Explorer—and share from there if you want. Nice.
And since Share is available from File Explorer, that means it will be available to all desktop applications too. This will likely require developers to add that functionality to their applications, and of course Microsoft hasn't yet detailed the new APIs and developer platform-related capabilities in Windows 10. But this is one of them.