It seems to be mono version mismatch.When rendering iOS designer in Visual Studios Windows, the following command is supposed to be executed on the other side, MacOS./Library/Frameworks/Mono.framework/Commands/mono64 /Users/jeremyroh/Library/Caches/Xamarin/XMA/Agents/Designer/agent-xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/CSProxyHost.exeThe command always causes an exception with mono 5.12.0Even though I tried a few different version of 5.12.0.xxx, it didn't give any difference. Only if I used mono 5.16.0 the latest version, the command executed fine without any exceptions, errors. But, Visual Studio iOS agent forces to use mono 5.12.0.Expected fix should be either to allow to use mono 5.16.0 or to fix of CSProxyHost.exe with mono 5.12.0. From my mono - version: Mono JIT compiler version 5.12.0.309 (2018-02/39d89a335c8 Thu Sep 27 06:54:53 EDT 2018) Copyright (C) 2002-2014 Novell, Inc, Xamarin Inc and Contributors.
Www.mono-project.com TLS: normal SIGSEGV: altstack Notification: kqueue Architecture: amd64 Disabled: none Misc: softdebug Interpreter: yes LLVM: yes(3.6.0svn-mono-release60/8b1520c8aae) GC: sgen (concurrent by default) In the previous version of VS (15.8) i had problems with editing the story board, which i got around by removing references to my.net project from my IOS project. This workaround no longer works as of this latest update.
Visual Studio for Mac is an evolution of Xamarin Studio, and includes all the functionality of Xamarin Studio 6.3. If you already have VS for Mac installed, this update will appear in any of the updater channels within the IDE. Xamarin Studio for Mac and Visual Studio for Windows. Staying on Mac with Xamarin Studio is better choice for iOS development (VS have some issues and poor performance sometime with Xamarin.iOS), personal experiment.