Json.NET JsonConvert.DeserializeObject() return null value

I forgot to make the properties public. Don't forget to do that...

In the interest of helping others that may be experiencing this issue, or one related to it...

In my case, I had an object with an array of other objects, and one of the reference-type properties on those sub-objects was always null after deserialization. I tried all kinds of things, including downloading the JSON.Net source and stepping through it to find the failure point.

To make a long story short, the problem was, of course, my own. Here is a highly simplified version of my JSON and classes.

JSON

{
    "$id": "1",
    "RowCount": 10,
    "Rows": [{
        "$id": 2",
        "ItemId": "1",
        "ItemName": "Some Item",
        "Owner": {
            "Name": "John Doe",
            "Id": "711D04F5-586F-4FD4-8369-4C00B51DD86F",
            // other properties...
        },
        "OwnerId": "711D04F5-586F-4FD4-8369-4C00B51DD86F"
    },
    // more rows
    ]
}

Classes

public class Items
{
    public int RowCount { get; set; }
    public IEnumerable<Item> Rows { get; set; }
}

public class Item
{
    private string ownerId;

    public string ItemId { get; set; }
    public string ItemName { get; set; }
    public Person Owner { get; set; }
    public string OwnerId
    {
        get { return this.ownerId; }
        set {
            if (value != this.ownerId)
            {
                this.Owner = null;
            }
            this.ownerId = value;
        }
    }
}

public class Person
{
    public string Name { get; set; }
    public string Id { get; set; }
    // other properties
}

What was happening is that, because the Owner property appeared in the JSON prior to the OwnerId property, when the OwnerId property was set, the setter code determined that the current value was not the same as the value being set (since the current value was null), so it set the Owner property to null.

To fix it I also check the value being set against the id of the Owner object as well, and skip setting Owner to null if they are the same.

Admittedly, the cause of my problem may not be the same for everyone, but this is at least a cautionary tale to double-check what is happening when your objects are being initialized during deserialization.