Weird behavior during parsing Json

Question

I'm parsing this JSON

{"error":null,"result":{"KIBAUSDT":{"limit":100,"offset":0,"total":2,"records":[{"user":2996434,"id":82873069172,"market":"KIBAUSDT","freeze":"100","fee_stock":"","source":"web","type":1,"side":1,"ctime":1645133452.181028,"mtime":1645133452.181028,"price":"0.00002","amount":"100","taker_fee":"0.0035","maker_fee":"-0.003","left":"100","deal_stock":"0","deal_money":"0","deal_fee":"0","alt_fee":"0","deal_fee_alt":"0","status":0},{"user":2996434,"id":82873306723,"market":"KIBAUSDT","freeze":"100","fee_stock":"","source":"web","type":1,"side":1,"ctime":1645133526.563619,"mtime":1645133546.966621,"price":"0.00001124","amount":"200","taker_fee":"0.0035","maker_fee":"-0.003","left":"100","deal_stock":"100","deal_money":"0.001124","deal_fee":"-0.000003372","alt_fee":"0","deal_fee_alt":"0","status":1}]}},"id":300991746}

which is basically the API of one crypto exchange that is showing the orders that I've opened. I'm using quicktype.io to create the code of a new class file

Imports System
Imports Newtonsoft.Json
Imports Newtonsoft.Json.Converters
Imports System.Runtime.CompilerServices

Namespace OrdiniAperti
    Partial Public Class Openorders
        
        Public Property [Error] As Object
        
        Public Property Result As Result
        
        Public Property Id As Long
    End Class

    Partial Public Class Result
        
        Public Property Kibausdt As Kibausdt
    End Class

    Partial Public Class Kibausdt
        
        Public Property Limit As Long
        
        Public Property Offset As Long
        
        Public Property Total As Long
        
        Public Property Records As Record()
    End Class

    Partial Public Class Record
        
        Public Property User As Long
        
        Public Property Id As Long
        
        Public Property Market As String
        
        Public Property Freeze As String
        
        Public Property FeeStock As String
        
        Public Property Source As String
        
        Public Property Type As Long
        
        Public Property Side As Long
        
        Public Property Ctime As Double
        
        Public Property Mtime As Double
        
        Public Property Price As String
        
        
        Public Property Amount As Long
        
        Public Property TakerFee As String
        
        Public Property MakerFee As String
        
        
        Public Property Left As Long
        
        
        Public Property DealStock As Long
        
        
        Public Property DealMoney As Long
        
        
        Public Property DealFee As Long
        
        
        Public Property AltFee As Long
        
        
        Public Property DealFeeAlt As Long
        
        Public Property Status As Long
    End Class

    Partial Public Class Openorders
        Public Shared Function FromJson(ByVal json As String) As Openorders
            Return JsonConvert.DeserializeObject(Of Openorders)(json, Settings)
        End Function
    End Class

    Public Module Serialize
        
        Public Function ToJson(ByVal self As Openorders) As String
            Return JsonConvert.SerializeObject(self, Settings)
        End Function
    End Module

    Friend Module Converter
        Public ReadOnly Settings As JsonSerializerSettings = New JsonSerializerSettings With {
            .MetadataPropertyHandling = MetadataPropertyHandling.Ignore,
            .DateParseHandling = DateParseHandling.None
        }
    End Module

    Friend Class ParseStringConverter
        Inherits JsonConverter

        Public Overrides Function CanConvert(ByVal t As Type) As Boolean
            Return t Is GetType(Long) OrElse t Is GetType(Long?)
        End Function

        Public Overrides Function ReadJson(ByVal reader As JsonReader, ByVal t As Type, ByVal existingValue As Object, ByVal serializer As JsonSerializer) As Object
            If reader.TokenType = JsonToken.Null Then Return Nothing
            Dim value = serializer.Deserialize(Of String)(reader)
            Dim l As Long

            If Long.TryParse(value, l) Then
                Return l
            End If

            Throw New Exception("Cannot unmarshal type long")
        End Function

        Public Overrides Sub WriteJson(ByVal writer As JsonWriter, ByVal untypedValue As Object, ByVal serializer As JsonSerializer)
            If untypedValue Is Nothing Then
                serializer.Serialize(writer, Nothing)
                Return
            End If

            Dim value = CLng(untypedValue)
            serializer.Serialize(writer, value.ToString())
            Return
        End Sub

        Public Shared ReadOnly Singleton As ParseStringConverter = New ParseStringConverter()
    End Class
End Namespace

and then I'm using the following code in order to parse some of the property I need:

 Dim json = Await wc1.DownloadStringTaskAsync("https://api.hotbit.io/api/v1/order.pending?market=KIBA/USDT&offset=0&limit=100&api_key=44812d8f-66d3-01c0-94c3b29305040b03&sign=F3330B924E1873B9C8FAB40A25D7B851")
                'deserialize the json
                Dim rootObj = Openorders.FromJson(json)
                'navigate to Kibausdt
                Dim kibausdt = rootObj.Result.Kibausdt

                'check total
                If kibausdt.Total = 0 Then
                    RichTextBox1.Text = "0 opened orders"

                Else
                    RichTextBox1.Clear()
                    'loop through records
                    For Each record In kibausdt.Records
                        Dim side As String = record.Side.ToString()
                        Dim amount As Long = record.Amount
                        Dim price As String = record.Price.ToString
                        Dim filled As Long = record.Left
                        Dim status As String = record.Status.ToString
                        If side = "1" Then
                            side = "SELL"
                        Else
                            side = ("BUY ")
                        End If
                        If status = "1" Then
                            status = "Hidden order"
                        Else
                            status = "Not hidden order"
                        End If
                        Dim percentage As Double = ((filled * 100) / amount)
                        RichTextBox1.Text &= "    " & side & " - " & "      " & amount & " - " & "            " & price.ToString & " - " & "    " & percentage.tostring & " % " & " - " & "    " & status & vbCr
                    Next
                End If

As you can see the API lack of filled % property, so I'm calculating it with the formula ((filled * 100)/ whole order amount). The code is working when I have 0 order opened and when an order ( or more) is opened but still not filled, so with 0% filled. The problem starts when the order is starting to be filled, so the % increase. As soon as the % moves from 0 I'm getting the error on the class file at the line Throw New Exception("Cannot unmarshal type long")

System.Exception: 'Cannot unmarshal type long'

So I've been looking at the class file code and sow that "left" and "amount" properties are declared as Long. So I've tried to declare them as Double and even as Decimal, So I changed also Dim filled As Long to Dim filled As Double as well as Dim amount as long to Dim amount as Double into the main form. But now, I'm getting the following error on the line Return JsonConvert.DeserializeObject(Of Openorders)(json, Settings) of the Class File:

Newtonsoft.Json.JsonSerializationException: 'Error setting value to 'Left' on 'HotBit_APIs.OrdiniAperti.Record

How is this behavior possible? What Am I doing wrong? Thanks

Answer

Hi @Mattia Fanti ,
I used the code you provided and got the exception Error setting value to 'DealMoney' on 'Deserialize_a_dictionary_json.Record'.
When I changed all long types to Decimal types, there were no exceptions.
And I got the following result.

Maybe you can try to change all long types to Decimal types.
Best Regards.
Jiachen Li

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Answer

I solved changing all "long" types to "Double"

Weird behavior during parsing Json

2 answers