Feature: Add Preview for Office files - Word, Excel

[Timeless4k]

Currently, you can only preview PDF file can we improve the preview menu to incorporate Word, Excel, TXT etc. When your click on the file you can see the preview of the file, just have the ability like the normal file explorer.

[gave92]

Hello, preview for .TXT files (and many others) it's already implemented. If you don't see it it's a bug. Preview for office files would be very nice to have.

[winston-de]

I've been looking into this, and unfortunately it would be very difficult to get a preview that is on par with Windows Explorer, as it essentially embeds the Word (or other Office) application inside of the preview pane. And, unlike PDFs, there is no built in API to render them, and all the third party ones I've found are paid (and expensive at that).
However, since there does seem to be a lot of interest in this, I will do my best to put something together.

Also, if someone just happens to know of a free library for rendering Office documents, please do share it.

[gave92]

Might try to generate a preview from the fulltrustprocess (using e.g. Microsoft interop) and send the render as images to uwp? Yuk

[generalguy41]

Not sure if it's been looked into already but Quicklook has an Office plugin. Maybe something from there can be used?

https://github.com/QL-Win/QuickLook.Plugin.OfficeViewer

[gave92]

Not directly as that's for wpf. But I believe we could try to get the equivalent for uwp. License for open source projects might be free.

[winston-de]

@gave92 That looks perfect.
It looks like the library has render as image capabilities for PowerPoint, and Excel files, so we could load and display those previews the same way as the PDF preview.
Apparently Word document to image isn't support on UWP, so we would have to either show the document editor control (a bit overkill for a preview), or convert it to a PDF stream and render that instead (could be slower).

However, this all would require:
A). Acquiring a open source license (and possibly having to follow the terms of said license)
B). Taking on several new rather large dependencies

@yaichenbaum What do you think?

[yaira2]

@winston-de Is it possible to use extensions for this or will we still need to add the dependencies?

[winston-de]

@yaichenbaum Extensions would work, as could an optional package.

[yaira2]

@winston-de Let's do this via an extension to avoid bundling an extra dependency with Files.