I'm using VB/.NET through Wonderware's ArchestraIDE Quickscript.net scripting language. I see there's quite a few ways to deal with JSON deserialization in .NET (DataContractJsonSerializer, JavaScriptSerializer, Json.net/Newtonsoft.Json) - but can't find any in the Wonderware subset.
It seems like JavaScriptSerializer isn't included as part of the .NET framework for Quickscript.NET, as ArchestrA doesn't recognise anything from System.Web.Script; and neither is DataContractJsonSerializer (System.Runtime.Serialization.Json isn't there).
I didn't find anything about json in the Quickscript.net docs either.
What is the standard/best way to deserialize JSON in this environment?
I'd recommend you to work on an external program to test JSON deserialization as a Stand-Alone method (using some third party libraries like Newtonsoft .NET) to compile it into a DLL. Then later import it to ArchestrA framework via the IDE and use your own method.
It will be a better approach since that with ArchestrA scripting you won't be able to declare classes or use listings, which are some things you should do when dealing with nice structured JSON deserialization for your better understanding.
Here's the catch, avoid compiling a code library that makes external reference to another one. ArchestrA's objects can't handle that external call in runtime, even if you import the other library and all other dependencies. There is a way to properly import a DLL that depends on other libraries to execute, but it's not the best practice in my opinion if you (or other unadvised person) are going to do future maintenance in your source code.
My final recommendation is to get the source code of open libraries (like Newtonsoft .NET), and make your program as a class alongside its project, and compile it into a single build. After that, you'll just need to import the library and do the proper method calls and classes instances.
If you prefer not to use a single compilation project, try to use ILMerge to merge the two libraries into one, even if they have a dependency, it works on ArchestrA objects at runtime.