Autofac.Extras.CommonServiceLocator doesn't work with Autofac 4.3.0+

[justinyoo]

Hi, Team.

Wonder if this is a known issue or not. I'm using Autofac.Extras.CommonServiceLocator 4.0.0 at my project. If I upgrade the Autofac version higher than 4.2.1, it throws an exception (xxxx masking intended):

Exception while executing function: xxxx. mscorlib: Exception has been thrown by the target of an invocation. xxxx: The type initializer for 'xxxx' threw an exception. xxxx: Method not found: 'Void Autofac.Extras.CommonServiceLocator.AutofacServiceLocator..ctor(Autofac.IComponentContext)'.

I tried 4.3.0, 4.4.0, 4.5.0 and 4.6.0 but all threw the same exception. Therefore I have to stay on 4.2.1 until this is fixed. Could you please let me know a workaround? I suspect that Autofac.Extras.CommonServiceLocator hasn't been updated for about a year, which resulted in failing to support .NET Standard.

Cheers,

[tillig]

The CommonServiceLocator package, last published in 2014, itself doesn't support .NET Standard/.NET Core. There's an unofficial fork that appears to be compatible, but that's not the official one and isn't something we support.

The PCL profile targeted by CommonServiceLocator looks like: portable-net40+sl5+win8+wp8+wpa81.

Looking at the netstandard docs under the PCL compatibility section I don't see any with the sl5 (Silverlight 5) support or net40 support. .NET 4.5 is the lowest it goes along with wp8 (Windows Phone 8).

I was able to create a .NET 4.5.2 app and a .NET 4.6.2 app using

• CommonServiceLocator 1.3.0
• Autofac 4.6.0
• Autofac.Extras.CommonServiceLocator 4.0.0

and it works.

I tried getting a console app targeting netcoreapp1.1 to work but you get into some odd hacky package target fallback stuff and VS starts telling me to add a reference to mscorlib 2.0.5.0 which is a weird retargetable placeholder thing used in Portable Class Libraries.

Short version is: CommonServiceLocator itself doesn't really support the scenario so there's not much we can do about that.

Do you have some repro where you are targeting .NET Core / .NET Standard where you didn't have to manually hack package references in and it was working? I can't find the magic combination that will fool NuGet into allowing me to even add CommonServiceLocator to a netstandard/netcoreapp project.

[justinyoo]

@tillig Thanks for your kind explanation! So, basically it's because the CommonServiceLocator library doesn't support .NET Standard and the library is apparently not being maintained any longer.

I have a toy project (Azure Functions) that relies on Autofac.Extras.CommonServiceLocator. Many of dependencies that my project is using are based on .NET Standard. If you don't mind, you can have a look at the repo and find out some workaround.

https://github.com/aliencube/yarm

[tillig]

Unfortunately I don't really have time to offer deep individualized help like that. Without even looking, though, I can tell you the replacement will be one of these:

• Use Autofac directly rather than the CSL wrapper.
• Replace CSL with Microsoft.Extensions.DependencyInjection and Autofac.Extensions.DependencyInjection.
• Roll your own CSL and adapt Autofac to that.
• Use the unofficial fork of CSL that supports .NET Core and adapt Autofac to that.
• Stop using service location to avoid the issue altogether.

You'll have to choose the best option for you.

You might also see if you can submit a PR to CSL but if they're not maintaining it anymore that may be hard.

[justinyoo]

@tillig Sorry for asking the individualised help. I might have misinterpreted your last paragraph:

Do you have some repro where you are targeting .NET Core / .NET Standard where you didn't have to manually hack package references in and it was working?

However, your suggestion is invaluable! I'll have a look one of those options that can be applied to my situation.

[tillig]

Oh, yeah, sorry for confusion. On mobile over the long holiday weekend here in the US. When I was asking for a repro I meant "a small, very simple reproduction showing a project where NuGet allowed you to somehow add the packages in the unsupported configuration" rather than "link to a repo full of projects to navigate through." Apologies for the confusion, but glad I could help. Good luck!