Issue accessing deserialized json data

Question

I'm new to webhooks and json but have been searching this site and the rest of google trying to figure out how to process a sendgrid json post for a project I'm working on. I have the code working functionally but get either nothing/empty string returned for my data or an error (for unique args).

I'm using newtsonsoft.json and currently just posting to an aspx page and trying to output the data to tets the process. I have a fixed sample json post that I'm sending.

All info below - would really appreciate someone advising me where I've screwed up please as I've been searching for samples and solutions and am stuck!

Code

Public Class sgData

    Public Property sgEmail() As String
    Public Property sgTimestamp() As String
    Public Property sgSMTPID() As String
    Public Property sgEvent() As String
    Public Property sgCategory() As String
    Public Property sgEventID() As String
    Public Property sgMsgID() As String
    Public Property sgUserAgent() As String
    Public Property sgIP() As String
    Public Property sgURL() As String
    Public Property sgASMGroup() As String
    Public Property sgUniqueArgs As uArgs

End Class

Public Class uArgs

    Public Property CB() As String
    Public Property emailType() As String
    Public Property prodGroup() As String

End Class

Public Class xhandler

    Inherits System.Web.UI.Page
    Implements System.Web.IHttpHandler

    Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.Load

        Dim whReader As New StreamReader(HttpContext.Current.Request.InputStream)
        Dim strjson = whReader.ReadToEnd()
        Dim sgResponse = JsonConvert.DeserializeObject(Of List(Of sgData))(strjson)
        For Each item In sgResponse
            HttpContext.Current.Response.Write("-> event=" & item.sgEvent & Chr(13))    ' is empty/nothing
            HttpContext.Current.Response.Write("-> CB=" & item.sgUniqueArgs.CB & Chr(13))    ' throws an error = Object reference not set to an instance of an object
        Next

    End Sub

End Class

And the json content...

[
  {
    "email": "example@test.com",
    "timestamp": 1517928354,
    "smtp-id": "<14c5d75ce93.dfd.64b469@ismtpd-555>",
    "event": "processed",
    "category": "cat facts",
    "sg_event_id": "uMaJLSrLHH96LFwwpCju5w==",
    "sg_message_id": "14c5d75ce93.dfd.64b469.filter0001.16648.5515E0B88.0",
    "unique_args": {
        "CB": "111",
        "emailType": "invite",
        "prodGroup": "REFEX"
    }
  },
  {
    "email": "example@test.com",
    "timestamp": 1517928354,
    "smtp-id": "<14c5d75ce93.dfd.64b469@ismtpd-555>",
    "event": "deferred",
    "category": "cat facts",
    "sg_event_id": "3pSLStZrkwJ52nPCBa6z-Q==",
    "sg_message_id": "14c5d75ce93.dfd.64b469.filter0001.16648.5515E0B88.0",
    "response": "400 try again later",
    "attempt": "5",
    "unique_args": {
        "CB": "222",
        "emailType": "invite",
        "prodGroup": "REFEX"
    }
  }
]

Answer 1

Just use a JSON library like Json.NET to parse your string. Maybe this could help you.

Answer 2

OK sorted it. Just deserialized it directly into an object and then deserialized the unique_args into a dictionary to lop through, completely ignoring the classes I created.

Working code snippet below:

Dim sgResponse = JsonConvert.DeserializeObject(strjson)
For Each item In sgResponse
    sgEventType = item("event").ToString
    candEmail = item("email").ToString
    Dim uniqueArgs = JsonConvert.DeserializeObject(Of Dictionary(Of String, Object))(item("unique_args").ToString)
    CB = uniqueArgs("CB")
    emailType = uniqueArgs("emailType")
    prodGroup = uniqueArgs("prodGroup")
    HttpContext.Current.Response.Write("-> event=" & sgEventType & ", email=" & candEmail & ", CB=" & CB & ", emailType=" & emailType & ", prodGroup=" & prodGroup & Chr(13))
Next

And it outputs the following:

-> event=processed, email=example@test.com, CB=111, emailType=invite, prodGroup=REFEX
-> event=deferred, email=example@test.com, CB=222, emailType=invite, prodGroup=REFEX

thx, just couldn't get my head around it earlier for some reason :-D