What is best practice of Newtonsoft deserialization of an object with read only properties?

Question

There isn't much documentation on how newtonsoft deserialize object

This suggest that with newtonsoft we need to use (non read only) public properties. Of course I do not want to use (non read only) public properties. I use only read only public properties.

But that causes problem

https://www.newtonsoft.com/json/help/html/SerializingJSON.htm

Basically I have a simple class (I simplify it so you can see)

Class gridTradingState


    ReadOnly Property bidInBase As Decimal
    ReadOnly Property askInBase As Decimal
    ReadOnly Property high As Decimal
    ReadOnly Property low As Decimal
    ReadOnly Property dateSinceLastTransactions As Date
    ReadOnly Property suggestedLow As Decimal
    ReadOnly Property suggestedhigh As Decimal
end class

See. It's a simple class.

The json looks like this (I've changed the code after but should not be much different. As far as I know, none)

{"bidInBase":0.00033485,"askInBase":0.00034407,"highInBase":0.00045,"lowInBase":0.00025797,"dateSinceLastTransactions":"2022-11-21T20:48:00.1243771+07:00","suggestedLow":0.0002,"suggestedhigh":0.0006}]}

The class doesn't have any default new contractor

In Why I cannot deserialize objects that I just serialized? I asked why it doesn't work.

What happened is newtonsoft will default using the default contractor and then set the properties.

The problem is for newtonsoft to set the properties from outside the class, the properties must be public. Well I do not like public properties.

So how to resolve that dilemma?

Currently the way I am doing it is

I put these

Protected Sub New(bidInBase As Decimal, askInBase As Decimal, highInBase As Decimal, lowinbase As Decimal, orders As OrderAlreadyPlacedAtanExchange(), dateSinceLastTransactions As Date)
    _bidInBase = bidInBase
    _askInBase = askInBase
    _highInBase = highInBase
    _lowInBase = lowinbase
    _dateSinceLastTransactions = dateSinceLastTransactions
End Sub



Public Shared Function creategridtradingOldStateFromJson(json As String) As gridTradingState

    Dim jo = JToken.Parse(json)
    Dim dateInJson = Convert.ToDateTime(jo.Item("dateSinceLastTransactions").ToString)
    'Dim \
    Dim orders As OrderAlreadyPlacedAtanExchange() = Nothing
    Dim output = New gridTradingState(CDec(jo.Item("bidInBase")), CDec(jo.Item("askInBase")), CDec(jo.Item("high")), CDec(jo.Item("low")), orders, dateInJson)
    Return output

End Function

That is, I do not use deserialize at all. Instead I just manually insert those stuffs one by one.

And that can't be the right way to do it.

So what is the right way to deserialize a class?

We want public read only variables by the way.

You have to show your json, otherwise nobody can telll you anything — Serge, Nov 16 '22 at 21:24
okay hang on. the json is kind of obvious for something as simple as that actually — user4951, Nov 21 '22 at 08:25
I suspect the right way is to use property with public get and private set. I didn't know it when I asked this question and I am still not sure. If that's true please answer. — user4951, Nov 21 '22 at 14:06

score 1 · Answer 1 · answered Nov 21 '22 at 14:37

If you have a constructor with parameters that matches the names in the json it will work and the properties can be readonly.

Sub Main
    Dim json As String = "
    {
       ""bidInBase"":0.00033485,
       ""askInBase"":0.00034407,
       ""high"":0.00045,
       ""low"":0.00025797,
       ""dateSinceLastTransactions"":""2022-11-21T20:48:00.1243771+07:00"",
       ""suggestedLow"":0.0002,
       ""suggestedhigh"":0.0006
    }"
    Dim result = JsonConvert.DeserializeObject(Of gridTradingState)(json)
End Sub

Class gridTradingState
    ReadOnly Property bidInBase As Decimal
    ReadOnly Property askInBase As Decimal
    ReadOnly Property high As Decimal
    ReadOnly Property low As Decimal
    ReadOnly Property dateSinceLastTransactions As Date
    ReadOnly Property suggestedLow As Decimal
    ReadOnly Property suggestedhigh As Decimal

    Public Sub New(bidInBase As Decimal, askInBase As Decimal, high As Decimal, low As Decimal, dateSinceLastTransactions As Date, suggestedLow As Decimal, suggestedhigh As Decimal)
        Me.bidInBase=bidInBase
        Me.askInBase=askInBase
        Me.high=high
        Me.low=low
        Me.dateSinceLastTransactions=dateSinceLastTransactions
        Me.suggestedLow=suggestedLow
        Me.suggestedhigh=suggestedhigh
    End Sub
End Class

That's what I actually used. Is this the best? – user4951 Nov 21 '22 at 15:11 — user4951, Nov 21 '22 at 15:11

What is best practice of Newtonsoft deserialization of an object with read only properties?

1 Answers1