[Solved] Newtonsoft JSON Read Error: Unexpected JSON token when reading DataTable. Expected StartArray

Hi makumbi,

You are using nested json so you need to create class for Root and transactions and use WebClient() method for reading JSON URL.Please refer below sample.

HTML 

<asp:GridView ID="gvDetails" runat="server"></asp:GridView>

Namespaces

C#

using System.Data;
using System.Net;
using Newtonsoft.Json;

VB.Net

Imports System.Data
Imports System.Net
Imports Newtonsoft.Json

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    if (!this.IsPostBack)
    {
        string json = (new WebClient()).DownloadString("https://schoolpay.co.ug/paymentapi/AndroidRS/SyncSchoolTransactions/233/2022-05-05/3B91DB220B7797416DD5417B2A3AFC95");
        Root root = JsonConvert.DeserializeObject<Root>(json);
        string transactions = JsonConvert.SerializeObject(root.transactions);
        DataTable dt = JsonConvert.DeserializeObject<DataTable>(transactions);
        this.gvDetails.DataSource = dt;
        this.gvDetails.DataBind();
    }
}

public class Root
{
    public int returnCode { get; set; }
    public string returnMessage { get; set; }
    public List<transaction> transactions { get; set; }
}

public class transaction
{
    public string amount { get; set; }
    public DateTime paymentDateAndTime { get; set; }
    public string schoolpayReceiptNumber { get; set; }
    public string sourceChannelTransDetail { get; set; }
    public string sourceChannelTransactionId { get; set; }
    public string sourcePaymentChannel { get; set; }
    public string studentName { get; set; }
    public string studentPaymentCode { get; set; }
    public string studentRegistrationNumber { get; set; }
    public string transactionCompletionStatus { get; set; }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    If Not Me.IsPostBack Then
        Dim json As String = (New WebClient()).DownloadString("https://schoolpay.co.ug/paymentapi/AndroidRS/SyncSchoolTransactions/233/2022-05-05/3B91DB220B7797416DD5417B2A3AFC95")
        Dim root As Root = JsonConvert.DeserializeObject(Of Root)(json)
        Dim transactions As String = JsonConvert.SerializeObject(root.transactions)
        Dim dt As DataTable = JsonConvert.DeserializeObject(Of DataTable)(transactions)
        Me.gvDetails.DataSource = dt
        Me.gvDetails.DataBind()
    End If
End Sub

Public Class Root
    Public Property returnCode As Integer
    Public Property returnMessage As String
    Public Property transactions As List(Of transaction)
End Class

Public Class transaction
    Public Property amount As String
    Public Property paymentDateAndTime As DateTime
    Public Property schoolpayReceiptNumber As String
    Public Property sourceChannelTransDetail As String
    Public Property sourceChannelTransactionId As String
    Public Property sourcePaymentChannel As String
    Public Property studentName As String
    Public Property studentPaymentCode As String
    Public Property studentRegistrationNumber As String
    Public Property transactionCompletionStatus As String
End Class

Screenshot