Fix bug #293 Incorrect serialization of Enums

[cruiserkernan]

Fix Incorrect Serialization of Enums in BlazorGoogleMaps

Description

This pull request addresses a critical issue in the BlazorGoogleMaps repository concerning the incorrect serialization of enums. The issue not only affected the positioning of map controls but might have also impacted other parts of the library due to improper use of the EnumMember attribute in JSON serialization.

Changes Made

• Added the JsonConvert attribute to all enums using the JsonStringEnumConverterEx converter.
• Ensured that all enums use JsonStringEnumConverterEx instead of JsonStringEnumConverter.
• Updated the JsonStringEnumConverterEx class to be a factory for converters, utilizing a concurrent dictionary for caching converters. This allows only one converter to be added to the JsonSerializerOptions, improving performance and consistency across the library.

Impact

• These changes ensure that enums are serialized correctly, respecting the EnumMember attribute.
• The update to the JsonStringEnumConverterEx class enhances the efficiency and reliability of the serialization process across the library.
• By fixing these serialization issues, the overall functionality and usability of the entire BlazorGoogleMaps library should be improved.

Please review the changes and let me know if there are any further modifications required. Looking forward to the feedback.

Thank you!

[valentasm1]

I was kinda aware of this. When i finished migration to system.text.json i had some issues did quick fixes and all seems working. IMO this PR is just shifting responsibility from prop atribute to enum. I am not saying it is wrong. Need to think more about this.

[cruiserkernan]

Let me know if you need any help implementing it any other way, if you do not have time to do it.

[valentasm1]

I am thinking this way. Added serializer to enum is harder to forget than compared to prop. Thats obvious. Just lats thing. Why you cache converters for each enum type? For all types it is the same Why not just return it?

[cruiserkernan]

Since there are some code running in the EnumConverter constructor for each enum type. I am caching the creation of each EnumConverter so that it only happens once. But maybe it is not needed?

[valentasm1]

I dont see any reason why you need to cache it. If you know any let me know. I just tried create 1mln converters and it took 15ms

[cruiserkernan]

I noticed while using this change in my app that it does not handle nullable enums. I made a change to the converter that takes care of it. I'm not sure if that is of any interest for you? Also as a side note I noticed when using these code changes that animation of markers started working.

[valentasm1]

Handling nullable enums is important. Maybe i didnt noticed but marker animations was always working. I will try merge this today.