C# Properties/Fields and Serialization

I was dealing with an odd dilemma while updating an ASP.Net MVC API. I had created 2 new classes to represent the data the front end was going to POST.

Here's the 2 class definitions in question:

    public class GraphicModel
    {
        public string Title { get; set; }
        public string Description { get; set; }
        public string Byline { get; set; }
        public string BylineTitleId { get; set; }
        public string BylineTitleDescription { get; set; }
        public string Category { get; set; }

        public List<GraphicBinary> GraphicBinaries;
    }

and:

    public class GraphicBinary

    {

        public SubmittedImageType ImageType { get; set; }

        public string OriginalFilename { get; set; }

        public string ItemId { get; set; }

        public string RecordId { get; set; }

        public int RecordSequenceNumber { get; set; }

    }

I had set things up on the front end to post the following JSON:

{

    "Title": "AP Poll Stay at Home Protest Approval",

    "Description": "A new UChicago Divinity School/AP-NORC poll finds that two-thirds of Democrats and about half of Republicans disapprove of recent protests of stay at home orders.;",

    "Byline": "F. Strauss",

    "BylineTitleDescription": "STAFF",

    "BylineTitleId": "STF",

    "Category": "a",

    "GraphicBinaries": [

        {

            "ImageType": "PrintGraphicAI",

            "ItemId": "dd142b48fe7c4cc6bf9b42c9c9402e7d",

            "RecordId": "dd142b48fe7c4cc6bf9b42c9c9402e7d",

            "RecordSequenceNumber": 0,

            "OriginalFilename": "ChicagoShootings.ai"

        },

        {

            "ImageType": "PrintGraphicJPEG",

            "ItemId": "ccce25ddc1cb45d898b09eb0d91fcecc",

            "RecordId": "ccce25ddc1cb45d898b09eb0d91fcecc",

            "RecordSequenceNumber": 0,

            "OriginalFilename": "ChicagoShootings.jpg"

        }

    ]

}

Here's the signature on my controller method:

    [HttpPost]

    public JsonResult Graphic(PhotoAction actionType, bool hid, GraphicSubmission graphicModel)

What was happening is the method was invoked properly but the GraphicBinaries field was always empty even though the JSON was correct. 

I posted a question on Stack Overflow (greatest site on earth!) here:

https://stackoverflow.com/questions/61880755/asp-net-controller-improperly-deserializing-nested-list-of-objects

The long and short of it is there's a difference between fields and properties in C# as noted here:

https://stackoverflow.com/questions/295104/what-is-the-difference-between-a-field-and-a-property

This is critical because only properties are serialized/deserialized and the GraphicBinaries field was a field not a property!