I am maintaining an old .NET Framework application (v4.7.2). It currently uses an in-house solution to send emails and read a mailbox on an Exchange Server, but this solution is being decommissioned and all applications are supposed to move to Microsoft Graph.
I have used MS Graph in other applications that are written in .NET Core, and it works in all of those. However, I cannot get it to work in this .NET Framework one.
This repository contains two soltutions:
- a .NET Framework 4.8.1 version with the same code as below, which does not work:
- the authentication succeeds, but the code throws an exception when trying to send emails.
- a .NET (Core) 6 version, which features virtually the same code, which does work.
Both use the same NuGet package: MS Graph 4.54.0 and its dependencies.
The .NET (Core) 6 solution contains virtually the same code as the .NET Framework version.
To me it signals that the NuGet package does not work correctly with .NET Framework. If that is indeed the case, it is a major problem for me since upgrading the legacy project to .NET Core is not a feasible solution in the short term (since it would require a significant rewrite).
If you download either solution to test locally, please read the README in the root of each solution:
each project lacks a file containing the necessary configuration settings,
but an example of what it should look like is present in the README file
(app.config for the .NET Framework solution, appsettings.json for the .NET 6 solution).
You will need to provide the necessary TenantId etc. yorself, of course.