Imports System

Imports System.Linq

Imports System.Collections

Imports System.Collections.Generic

Imports System.Data

Imports System.IO

Imports System.Globalization

Imports System.Reflection

Imports System.ComponentModel.DataAnnotations

Imports System.Xml.Linq

Imports System.Xml

​

Imports Newtonsoft.Json

Imports Newtonsoft.Json.Linq

Imports Newtonsoft.Json.Converters

Imports Newtonsoft.Json.Serialization

​

Imports NUnit.Framework

​

    ' https://stackoverflow.com/questions/56315777/how-to-deserialize-big-json-data-into-datagridview

​

    Public Class RootObject

        Public Property Email As String

        Public Property Timestamp As String

        Public Property Number As Long

    End Class

​

    Public Module JsonExtensions

        Public Function LoadAnonymousType(Of T)(ByVal path as String, ByVal anonymousTypeObject as T, Optional ByVal settings as JsonSerializerSettings = Nothing) as T

            Using streamReader As TextReader = File.OpenText(path)

                Dim serializer = JsonSerializer.CreateDefault(settings)

                return CType(serializer.Deserialize(streamreader, GetType(T)), T)

            End Using

        End Function

    End Module

​

    Public Module TestClass 

        Friend Sub Test()

            Dim FileName As String = "Question56315777.json"

​

            File.WriteAllText(FileName, GetJson())

​

            Try 

                TestAnonymous(FileName)

​

                Console.WriteLine()

​

                TestExplicit(FileName)

​

            Finally

                File.Delete(FileName)

            End Try

        End Sub 

​

        Friend Sub TestAnonymous(FileName as String)

            Console.WriteLine("Deserializing an array of anonymous objects:")

​

            Dim array = JsonExtensions.LoadAnonymousType( _

                FileName, _

                { New With {.Email = CType(Nothing, String), .Timestamp = CType(Nothing, String), .Number = CType(Nothing, Long) }} _

            )

            For Each item In array

                ' DataGridView1.Rows.Add(item("EMail").ToString, item("Timestamp").ToString, item("Number").ToString)

                Console.WriteLine("Email = {0}, Timestamp = {1}, Number = {2}", item.Email, item.Timestamp, item.Number)

            Next

        End Sub 

​

        Friend Sub TestExplicit(FileName as String)

            Console.WriteLine("Deserializing a list of RootObjects:")

​

            Dim list As List(Of RootObject) = Nothing

            Using streamReader As TextReader = File.OpenText(FileName)

                list = CType(JsonSerializer.CreateDefault().Deserialize(streamReader, GetType(List(Of RootObject))), List(Of RootObject))

            End Using

            For Each item In list

                ' DataGridView1.Rows.Add(item("EMail").ToString, item("Timestamp").ToString, item("Number").ToString)

                Console.WriteLine("Email = {0}, Timestamp = {1}, Number = {2}", item.Email, item.Timestamp, item.Number)

            Next

        End Sub 

​

        Function GetJson() as String

Dim Jstring As String = <![CDATA[

[

  {

    "EMail": "one@mail.com",

    "Timestamp": "2019-05-25T21:24:06.799381+02:00",

    "Number": 206074,

    "randomtrash1": "notneeded",

    "randomtrash2": "notneeded",

    "randomtrash3": "notneeded",

    "randomtrash4": "notneeded",

    "randomtrash5": "notneeded",

    "randomtrash6": "notneeded",

    "randomtrash7": "notneeded",

    "randomtrash8": "notneeded",

    "randomtrash9": "notneeded"

  },

  {

    "EMail": "two@mail.com",

    "Timestamp": "2019-05-25T21:24:06.8273826+02:00",

    "Number": 7397,

    "randomtrash1": "notneeded",

    "randomtrash2": "notneeded",

    "randomtrash3": "notneeded",

    "randomtrash4": "notneeded",

    "randomtrash5": "notneeded",

    "randomtrash6": "notneeded",

    "randomtrash7": "notneeded",

    "randomtrash8": "notneeded",

    "randomtrash9": "notneeded",

    "randomtrash10": "notneeded",

    "randomtrash11": "notneeded",

    "randomtrash12": "notneeded",

    "randomtrash13": "notneeded",

    "randomtrash14": "notneeded",

    "randomtrash15": "notneeded",

    "randomtrash16": "notneeded",

    "randomtrash17": "notneeded",

    "randomtrash18": "notneeded",

    "randomtrash19": "notneeded",

    "randomtrash20": "notneeded",

    "randomtrash21": "notneeded"

  }

]

]]>.Value       

        Return Jstring      

        End Function

    End Module

​

    Public Module Module1   

        Public Sub Main()

        Console.WriteLine("Environment version: " & Environment.Version.ToString())

            Console.WriteLine("Json.NET version: " & GetType(JsonSerializer).Assembly.FullName)

            Console.WriteLine("")

​

            Try

​

                TestClass.Test()

​

            Catch ex as Exception

​

                Console.WriteLine("Unhandled exception: ")

                Console.WriteLine(ex)

                Throw

​

            End Try

        End Sub 

    End Module

​

​