Add MAPI support to allow Store apps send custom emails using a preferred email client

[xyzzer]

Proposal: Add MAPI support to allow Store apps send mail

Summary

Create an API similar to MAPI to allow Store apps to interact with mail apps like Outlook to share their content via email, allowing API users to define rich email body with inline images, file attachments, subject, to, cc, bcc fields that users can then edit in their MAPI client of choice before sending the email from their own email address.

Rationale

Since the creation of WinRT - Store app developers who wanted to allow sharing content from their apps by email were limited to using a web service or the share contract, which isn't sufficient for rich email content. An app like Snipping Tool allows its users to provide a button that with one click enables sharing an image with their mail client of choice. Meanwhile, its UWP replacement, Snip & Sketch is limited to using the share contract, which requires selecting a share target app and doesn't allow prefilling any mail fields. It's also limited to mail apps that support the mail contract.

[jaigak]

@xyzzer There's an email API for WinRT apps and that doesn't use the share contract however it has a bug which prevents from sharing attachments to email apps other than Windows Mail. It also supports prefilling. https://docs.microsoft.com/en-us/windows/uwp/contacts-and-calendar/sending-email

[xyzzer]

I completely forgot about it, so sure - we could use that API if it were lifted and fixed to work in all common scenarios.

[stevewri]

@tfennel - this looks like a platform request for the share APIs, is this something your team would handle for Reunion?

[xyzzer]

• @jonwis for potential background

[jaigak]

Another thing is many desktop apps provide an email option however that only works with desktop email clients and not UWP ones like Windows Mail.