Xamarin.forms: [Forms][iOS] Error CS1703 Multiple assemblies with equivalent identity Net standard 2.0 Automapper

Seems that automapper is using something that requires Reflection.Emit. That's not going to work in iOS.

@jassmith thanks for the comment. One question though, would Reflection.Emit cause a runtime error or a build error?

AutoMapper uses expression tree compilation, so eventually an Expression.Lambda(...).Compile(). We use Reflection.Emit for a couple of very targeted scenarios.

Basically for us to target iOS we need to make sure we have a target that doesn't use/reference Reflection.Emit at all?

The compile error sounds like the recent problems with 15.5 and binding redirects though.

I had the same problem. My solution was to use a project.json in my ios project like this:

{
  "dependencies": {
    "System.Reflection.Emit": {
      "version": "4.3.0",
      "exclude": "all"
    }
  },
  "frameworks": {
    "Xamarin.iOS,Version=v1.0": {}
  },
  "runtimes": {
    "win": {}
  }
}

@gmwilhelm I didn't know the project.json was still a thing. Today I learn

@jassmith any chance you would review this ticket again? I know you've marked it invalid, but I think this is actually something Xam.Forms should address

I’m trying to reproduce this locally with just a blank NuGet package that
references Reflection.Emit but does not use it. I got the compile error
once but then it mysteriously went away.

On Tue, Jan 2, 2018 at 5:54 PM Wade Baglin notifications@github.com wrote:

@jassmith https://github.com/jassmith any chance you would review this
ticket again? I know you've marked it invalid, but I think this is actually
something Xam.Forms should address

—
You are receiving this because you commented.
Reply to this email directly, view it on GitHub
https://github.com/xamarin/Xamarin.Forms/issues/1380#issuecomment-354906852,
or mute the thread
https://github.com/notifications/unsubscribe-auth/AAGYMoqgqceTH4BPe4vqZwLkAoYb1YO0ks5tGsGxgaJpZM4Q-gOM
.

@pleb @jbogard

I am able to reproduce the Multiple Assemblies error in Visual Studio 15.5.5 but not in VSMac. I've created a DevCom item to track this.

FYI: in order to make the workaround above work you might need to restart your VS. That happened for me with VS for Mac.

@SvenEV had the solution in his commit
add this to the csproj file. If you are using PackageReferences

<PackageReference Include="System.Reflection.Emit" Version="4.3.0">
    <ExcludeAssets>all</ExcludeAssets>
</PackageReference>

I'm writing it here to make it more visible, As far as i have looked the emit Interface is used in Automapper to map for example to interfaces.