Create really simple samples for different platforms and providers

[ajcvickers]

For two reasons:

• To provide a simple starting point for getting-started
• To provide a starting point for issue reports--see https://github.com/dotnet/efcore/issues/20029

For the second point, we should also update the issue template.

Matrix:

• Platforms
  • [x] Console
  • [x] Blazor
  • [x] ASP.NET Core
  • [x] Windows Forms
  • [x] WPF
  • [ ] UWP/WinUI
  • [x] Xamarin
• Database providers
  • [ ] SQL Server
  • [x] SQLite
  • [ ] In-memory
  • [x] Cosmos
  • [ ] Npgsql
  • [ ] MySQL

(There is a lot of overlap here with other issues; we can de-dupe or not as appropriate as we make progress based on whether we also need more complex examples and also for creating the docs that reference the samples.)

[ajcvickers]

@dotnet/efcore Please add any providers and platforms I missed that you think are important. Also, please comment if you think some combination is not relevant/not important.

[AndriySvyryd]

To avoid combinations explosion consider creating a single project for all providers and use comments or preprocessor directives to allow easy switching.

And note that model building can be conditional, e.g.

if (context.Database.IsSqlServer())
{
}

Also don't do anything for the in-memory provider as we shouldn't encourage it to be used in this way.

[ajcvickers]

Also don't do anything for the in-memory provider as we shouldn't encourage it to be used in this way.

What if people are reporting bugs that only repro on the in-memory provider?

[AndriySvyryd]

What if people are reporting bugs that only repro on the in-memory provider?

Exactly what we are trying to avoid dealing with.

[ajcvickers]

@AndriySvyryd Not convinced. ;-)

[AndriySvyryd]

Just trying to save you time

[JohnGalt1717]

read the review comments on this... from the team that can't be bothered to do it for themselves and respect paying customers.... surreal. You should be in a panic to get this actually done and working and ready for your customers... instead you're nit picking?

[AndriySvyryd]

@JohnGalt1717 You can also use https://github.com/smitpatel/EFSampleApp before a more comprehensive solution is available

[JohnGalt1717]

I was just told that one would NEVER be available in another ticket that I just closed because I'm not going to put all of this effort in when the team at Microsoft (richest business in the world, paid $200,000 or so by my company a year) won't put effort in to get this setup in a comprehensive way and is copying and pasting code that sets up an empty Context and nothing else as if that somehow shortens the curve to replicate the endless bugs in EF Core 3.1 that didn't exist in EF Core 2.2