Create a draft email in Outlook 365 and then open it for editing

Question

We're planning to create draft Outlook 365 emails from our ASP.NET MVC C# code which is running as an Azure App. That looks relatively straightforward in the Outlook Mail REST API documentation and there's some useful info on that in this reply too .

What I'd then like to do is open that message in Outlook 365 in a new browser tab so the user can edit it before pushing send, but I can't seem to find a way to do that?

So, the process I'm trying to achieve is:

1. Create draft message in O365 Outlook using the Rest API
2. Save that draft
3. Open a new browser tab displaying that saved draft message in Outlook 365

Step 3 is what I can't find a way to do, is it possible?

If I open an email in Outlook 365 the URL is generic and doesn't contain a unique ID for the message object, so I'm not sure if there's any way to get a URL that links directly to an email message?

Answer 1

Alternatively if they're using on prem Outlook you could create a hyperlink using mailto: https://www.w3schools.com/tags/tryit.asp?filename=tryhtml_link_mailto

I have subsequently found this which should meet your criteria:

https://stackoverflow.com/a/40477920/4528266

https://blogs.msdn.microsoft.com/carloshm/2016/01/16/how-to-compose-a-new-message-or-event-and-populate-fields-in-office365/#comment-1645

Answer 2

If you need to keep the mail item after it is shown to a user you need to provide the UI in your application and use REST API for sending it. So, you will be able to refer to the item later.

As a possible workaround you may consider automating the desktop edition of Outlook installed on the machine. See C# app automates Outlook (CSAutomateOutlook) for more information.

Answer 3

Create draft message

https://docs.microsoft.com/en-us/graph/api/user-post-messages?view=graph-rest-1.0&tabs=http#example-1-create-a-new-message-draft-using-json-format

Open Draft https://outlook.office.com/mail/compose/MESSAGE_ID_GOES_HERE