Imports System

Imports System.Data

Imports Newtonsoft.Json.Linq

Public Module Module1

    Public Sub Main()

        Dim dt as New DataTable()

        dt.Columns.Add("InvNo", GetType(String))

        dt.Columns.Add("DateTime", GetType(String))

        dt.Columns.Add("Name", GetType(String))

        dt.Columns.Add("PhoneNumber", GetType(String))

        dt.Columns.Add("BillAmount", GetType(Decimal))

        dt.Columns.Add("Quantity", GetType(Decimal))

        dt.Columns.Add("Value", GetType(Decimal))

        dt.Columns.Add("Discount", GetType(Decimal))

        dt.Columns.Add("Type", GetType(Integer))

        dt.Columns.Add("Items", GetType(DataTable))

​

        Dim inner as New DataTable()

        inner.Columns.Add("I_Code", GetType(String))

        inner.Columns.Add("I_Name", GetType(String))

        inner.Columns.Add("I_Quantity", GetType(Decimal))

        inner.Columns.Add("I_TaxRate", GetType(Decimal))

        inner.Columns.Add("I_Sale", GetType(Decimal))

        inner.Columns.Add("I_T_Amount", GetType(Decimal))

        inner.Columns.Add("I_Discount", GetType(Decimal))

​

        inner.Rows.Add("IT_1011", "Test Item", 1.0, 0.0, 0.0, 0.0, 0.0)

        inner.Rows.Add("IT_1012", "Test Item", 1.0, 0.0, 0.0, 0.0, 0.0)

​

        dt.Rows.Add("1", "2020-01-01 12:00:00", "Customer Name", "0000-0000000", 0.0, 0.0, 0.0, 0.0, 1, inner)

​

        Dim json = JToken.FromObject(dt).First.ToString()

        Console.WriteLine(json)

​

    End Sub

End Module