Simple working Example of json.net in VB.net

Question

I have the following simplified JSON string from a provider, its been a long time since I used Visual Studio and vb.Net, so I'm very rusty!

{
"Venue": {
    "ID": 3145,
    "Name": "Big Venue, Clapton",
    "NameWithTown": "Big Venue, Clapton, London",
    "NameWithDestination": "Big Venue, Clapton, London",
    "ListingType": "A",
    "Address": {
        "Address1": "Clapton Raod",
        "Address2": "",
        "Town": "Clapton",
        "County": "Greater London",
        "Postcode": "PO1 1ST",
        "Country": "United Kingdom",
        "Region": "Europe"
    },
    "ResponseStatus": {
        "ErrorCode": "200",
        "Message": "OK"
    }
}
}

I want to use JSON.Net to turn this in to something I can work with, I have read examples etc and JSON.net looks like the answer, but I'm getting no where.

My .Net code (Me.TextBox1.Text contains the JSON shown above)

Imports Newtonsoft.Json

Public Class Form1

Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
    Dim obj As JSON_result
    obj = JsonConvert.DeserializeObject(Of JSON_result)(Me.TextBox1.Text)

    MsgBox(obj.ID)
End Sub
End Class

Public Class JSON_result
    Public ID As Integer
    Public Name As String
    Public NameWithTown As String
    Public NameWithDestination As String
    Public ListingType As String
 End Class

Can someone explain why obj.ID always ends up as 0 please, and why none of the other properties of my class are populated and what I need to do to fix this, no errors are reported.

sloth · Accepted Answer · 2014-02-10 12:18:48Z

32

Your class JSON_result does not match your JSON string. Note how the object JSON_result is going to represent is wrapped in another property named "Venue".

So either create a class for that, e.g.:

Public Class Container
    Public Venue As JSON_result
End Class

Public Class JSON_result
    Public ID As Integer
    Public Name As String
    Public NameWithTown As String
    Public NameWithDestination As String
    Public ListingType As String
End Class

Dim obj = JsonConvert.DeserializeObject(Of Container)(...your_json...)

or change your JSON string to

{
    "ID": 3145,
    "Name": "Big Venue, Clapton",
    "NameWithTown": "Big Venue, Clapton, London",
    "NameWithDestination": "Big Venue, Clapton, London",
    "ListingType": "A",
    "Address": {
        "Address1": "Clapton Raod",
        "Address2": "",
        "Town": "Clapton",
        "County": "Greater London",
        "Postcode": "PO1 1ST",
        "Country": "United Kingdom",
        "Region": "Europe"
    },
    "ResponseStatus": {
        "ErrorCode": "200",
        "Message": "OK"
    }
}

or use e.g. a ContractResolver to parse the JSON string.

answered Feb 10, 2014 at 12:18

sloth

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3 Comments

mikro Over a year ago

I use this site jsonutils.com to auto create classes for JSON strings to speed things up a bit. Thought I'd mention it for others.

sloth Over a year ago

There's also a VS plug in from Microsoft IIRC in some ASP.Net tool package but I forgot the name...

Wayne Barron Over a year ago

@mikro, Thank you for the link. That is going to come in very handy. THANK YOU!

DreamTeK · Accepted Answer · 2017-04-28 14:08:51Z

27

Imports Newtonsoft.Json.Linq

Dim json As JObject = JObject.Parse(Me.TextBox1.Text)
MsgBox(json.SelectToken("Venue").SelectToken("ID"))

edited Apr 28, 2017 at 14:08

DreamTeK

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answered Feb 10, 2014 at 12:33

Dibu

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1 Comment

Wild Teddy Over a year ago

You can install Newtonsoft from NuGet Package Manager. In VB 2019, you can find it in Tools - NuGet Package Manager - Manage NuGet Packages for Solution.

Lucifer666 · Accepted Answer · 2020-02-20 12:23:05Z

0

In Place of using this

MsgBox(json.SelectToken("Venue").SelectToken("ID"))

You can also use

MsgBox(json.SelectToken("Venue.ID"))

answered Feb 20, 2020 at 12:23

Lucifer666

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