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Documentation for Entity Framework Core and Entity Framework 6
https://docs.microsoft.com/ef/
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Workarounds for Xamarin.iOS app with EFCore 2.0 #597

Open bricelam opened 6 years ago

bricelam commented 6 years ago

Updated to current known issues and workarounds:

Good sample app link applying workarounds by @cwrea: https://github.com/cwrea/XamarinTodo/tree/master

Original Issue:

From @alexdrl on November 21, 2017 8:44

A Xamarin.iOS app with EFCore 2.0 needs a call to 

SQLitePCL.Batteries_V2.Init();

If the call is not made, the app initialization throws this error message. 

You need to call SQLitePCL.raw.SetProvider(). If you are using a bundle package, this is done by calling SQLitePCL.Batteries.Init().

Like explained here

Steps to reproduce

Xamarin.iOS project working with EFCore 2.0. Solution with a common .NET Standard project which shares code between iOS and Android, using PackageReference.

Further technical details

EF Core version: 2.0.0 Database Provider: Microsoft.EntityFrameworkCore.Sqlite Operating system: iOS IDE: Visual Studio 15.4

Copied from original issue: aspnet/EntityFrameworkCore#10361

bricelam commented 6 years ago

Correct. I don't think Xamarin.iOS can handle the Assembly.Load() call. And binding directly to SQLitePCLRaw.batteries_v2.dll will cause problems if you're not using a bundle.

bricelam commented 6 years ago

From @alexdrl on November 22, 2017 18:27

I use the SQLitePCLraw assembly that gets added as a transitive dependency, and call that Init method, the app works correctly. In the project assets json, the Xamarin.iOS SQLitePCLraw package gets restored correctly.

bricelam commented 6 years ago

We should probably document this on the Supported .NET Implementations page or thereabouts.

bricelam commented 6 years ago

From @alexdrl on November 22, 2017 18:31

The documentation already stated that there are problems in Xamarin.iOS but there is no page that describes this (or other) workarounds.

cwrea commented 6 years ago

Worth noting here, with respect to the Entity Framework Core 2.1 release, and the Visual Studio 15.7.3 releases of Xamarin.iOS and Xamarin.Android:

At present, the only known workaround for Xamarin mobile app developers wishing to use Entity Framework Core is to not upgrade to the 2.1 release. i.e. Stay on 2.0.3 until the underlying Xamarin platforms have addressed deficiencies related to the new System.Memory 4.5 dependency that was introduced (indirectly) as part of the newer packages that EF Core 2.1 now depends on. I am not aware of any timeline with respect to when these issues may be fixed.

dfoulk commented 6 years ago

@cwrea Thank you for mentioning this. I would've spent hours debugging that issue if I hadn't seen your comment first! Literally saved us hundreds of dollars!

cwrea commented 6 years ago

@dfoulk You're welcome. FWIW, since I posted that, there's hope that Visual Studio 15.8 Preview 3 may address these issues. See my comment from a couple of days ago at https://github.com/xamarin/xamarin-macios/issues/4168#issuecomment-398521666 ... I haven't tried the preview myself, yet. Tied up in other project work at the moment.

Pinox commented 6 years ago

@cwrea very weird. I'm running ef core 2.1 on my android and native UWP and it works and builds fine (debug and release) , but I'm using Microsoft.Extentions.primitives version 2.0

cwrea commented 6 years ago

@Pinox Do you have linking enabled? The oustanding Android issue is specific to having linking enabled.

Pinox commented 6 years ago

@cwrea In release mode I have "SDK Assemblies" and in debug mode "none".

Edit Ignore my comments as this morning my projects also do not work anymore with ef core 2.1