Add "PreviousVersionInstalled" to SystemInformation

[Panda-Sharp]

Currently SystemInformation contains the following properties:

• FirstVersionInstalled
• IsAppUpdated
• IsFirstRun
• ApplicationVersion

Would be nice to add a "PreviousVersionInstalled" to understand which version the app is updated from, to handle specific migration/changes.

Cheers

[Kyaa-dost]

@Panda-Sharp that's an interesting suggestion. Going to loop in @michael-hawker to see what he thinks about this addition in the list 🤔

[michael-hawker]

Yeah, seems good, provided details below. I like the PreviousVersionInstalled naming. @Sergio0694 that's a good convention for .NET stuff normally, eh?

[Sergio0694]

Mmh I'm thinking if we were to just write the whole type from scratch today, we'd probably want to slightly change the names to get more consistency, specificially with "Version" being a qualifying suffix here, so eg.:

• CurrentApplicationVersion
• FirstInstalledApplicationVersion
• PreviouslyInstalledApplicationVersion

That said, given the names we already have, I think calling the new one "PreviousVersionInstalled" is fine, as it's still self-explanatory and at least it's consistent with "FirstVersionInstalled", which is conceptually related to it 🙂

[michael-hawker]

@Panda-Sharp good point, seems like an oversight, and probably pretty easy to do... We do the detection right here:

https://github.com/windows-toolkit/WindowsCommunityToolkit/blob/385e4fb5bde53b9a28471c1e1b3dbf3dcb90a214/Microsoft.Toolkit.Uwp/Helpers/SystemInformation.cs#L339

We call that in the constructor right off the bat from here:

https://github.com/windows-toolkit/WindowsCommunityToolkit/blob/385e4fb5bde53b9a28471c1e1b3dbf3dcb90a214/Microsoft.Toolkit.Uwp/Helpers/SystemInformation.cs#L310

So I think all that needs to be done is to expose a property for the getter and set it instead of the local field and that'll be it! Just have to note that it'll only be different on that very first run when upgrading, as we then re-save the current version back over, just like the IsAppUpdated flag.

Want to open a PR? I'll convert this to an issue and assign to you if you'd like to contribute.

[Panda-Sharp]

Sounds good, I already went ahead and prepared some changes here , just two things that we can rediscuss in the issue eventually:

1. Is PreviousVersionInstalled naming fine? I forgot to write in the description that it was just an idea but I was open to better proposals of course
2. Currently the PreviousVersionInstalled fallback to the current version id there is no update, do you think is a good behavior? or should we fallback to default? Still we can understand if it's a version update checking the IsAppUpdated value

thanks

[Panda-Sharp]

@michael-hawker cc @Kyaa-dost

[michael-hawker]

Yeah, let's go with PreviousVersionInstalled. As for the behavior, I'm fine with either, probably easiest to just integrate it with the existing code and just document what that behavior is, i.e. that it'll just be the same version unless IsAppUpdated flag is set.