VB.Net JSON parsing - Error reading JObject from JsonReader. Current JsonReader item is not an object

Question

I've been searching high and low, and can't find a resolution to this so would welcome some guidance please. Spoiler - working in VB, not C# :-)

I have the following JSON data:

[{
    "payload": {
        "MainBlock": {
            "S0": {
                "interfaceId": "IF-XXX",
                "schemaVersion": "1.1.1",
                "eventCode": "[ABCPeriodData]"
            },
            "S1": {
                "environment": "DEV",
                "senderUniqueReference": "S-005-1234567abc-SUP-20222313-12345687A",
                "sentTimestamp": "2022-12-31T12:35:45\u002B06:30",
                "senderId": "4ce0a6cd4b",
                "senderRole": "ABC",
                "DIPConnectionProviderId": "1009012345"
            },
            "A0": {
                "always": ["SUP", "SDS", "ADS", "UMDS"]
            },
            "D0": {
                "transactionId": "T-022-4ce0a6cd4b-ABC-20230503-000404",
                "transactionTimestamp": "2023-05-03T13:34:34\u002B00:00",
                "publicationId": "PUB-XXX"
            }
        },
        "SecondBlock": {
            "B903List": [{
                "calculationDay": {
                    "calculationDayDate": "2022-12-31T12:35:45\u002B06:30",
                    "calculationPeriodDuration": 30
                },
                "XYZcalculationPeriods": [{
                    "XYZroup": {
                        "GSPGroupID": "_K",
                        "connectionTypeIndicator": "W",
                        "domesticPremiseIndicator": true,
                        "marketSegmentIndicator": "A",
                        "measurementQuantityID": "AI"
                    },
                    "XYZroupcalculationPeriods": [{
                        "calculationPeriodEffectiveToDateTime": "2022-12-31T12:35:45\u002B06:30",
                        "loadShapePeriodValue": "123456789.123",
                        "defaultLoadShapeFlag": "A"
                    }, {
                        "calculationPeriodEffectiveToDateTime": "2022-12-31T12:35:45\u002B06:30",
                        "loadShapePeriodValue": "123456789.123",
                        "defaultLoadShapeFlag": "A"
                    }]
                }]
            }]
        }
    }
}]

Using JSONLINT this validates as valid JSON data.

Trying to parse using Newtonsoft. I have already parsed a downloaded file successfully, and the data above is one of the values sent in an enclosing JSON file, so I know that parse method I have seems to work.

If I use the same method to parse the JSON above, as I did to parse the original download, it fails

Error reading JObject from JsonReader. Current JsonReader item is not an object: StartArray. Path '', line 1, position 1.

Using the following in a second parse method as the first one doesn't work on this. It would seem that I need to approach this particular type of JSON data differently.

            Dim o As JObject = JObject.Parse(Json)
            Dim results As List(Of JToken) = o.Children().ToList
            For Each item As JProperty In results
                item.CreateReader()
                If item.Value.Type = JTokenType.Array Then
                    Dim results2 As List(Of JToken) = item.Value.ToList
                    For Each subitem As JObject In results2
                        WorkingDictionary = New Dictionary(Of String, String)
                        Dim results3 As List(Of JToken) = subitem.Children().ToList
                        For Each temp2 As JProperty In results3
                            temp2.CreateReader()
                            Try
                                Debug.Print(temp2.Name)

                                WorkingDictionary.Add(temp2.Name, temp2.Value.ToString)

                                'Debug.Print(temp2.Name)
                                'Debug.Print(temp2.Value.ToString)
                            Catch ex As Exception
                                Debug.Print(ex.StackTrace)
                                Debug.Print(ex.Message)
                            End Try

                        Next
                        RetVal.Add(WorkingDictionary)
                    Next
                Else
                    Debug.Print(item.Name.ToString + "   " + item.Value.ToString)
                End If
            Next
            '         Next
        Catch ex As Exception
            Debug.Print(ex.StackTrace)
            Debug.Print(ex.Message)
        End Try

I've already looked at Newtonsoft.Json: Error reading JObject from JsonReader. Current JsonReader item is not an object: StartArray and none of them work.

Guidance welcome please, as parsing JSON is completely new to me.

Issue might be that the top-level item is an array and not a scalar? — Craig
– Craig, Commented May 4, 2023 at 15:07
You're saying For Each item As JProperty In results and then trying to use item as the JsonReader? I'm not sure about the parsing of the JObject; that looks fine to me. But maybe you want to change item.CreateReader() into something like Dim reader As JsonReader = item.CreateReader(). — Michael Foster
– Michael Foster, Commented May 4, 2023 at 19:20

Tym · Accepted Answer · 2023-05-05 12:48:27Z

0

There was a previous post from Serge which I was going to mark as the answer, but it's been deleted.

The code section should start with

Dim o As JArray = JArray.Parse(Json)

This is then the basis of parsing further as necessary.

If @serge would like to repost their original comment, I'd gladly mark as the accepted answer.

answered May 5, 2023 at 12:48

Tym

1132 silver badges17 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

VB.Net JSON parsing - Error reading JObject from JsonReader. Current JsonReader item is not an object

1 Answer 1

Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related