[Solved] Newtonsoft.Json Error: Additional text found in JSON string after finishing deserializing object

Hi mashispano,

The data returned by the url is an JArray object.

So you can't convert it to DataTable directly.

You need to loop through the JArray object to fetch the value.

Refer below sample code.

Namespaces

C#

using Newtonsoft.Json;
using Newtonsoft.Json.Linq;

VB.Net

Imports Newtonsoft.Json
Imports Newtonsoft.Json.Linq

Code

C#

protected void Page_Load(object sender, EventArgs e)
{
    var json = "[1,[\"R82.5\"],null,[[\"R82.5\",\"Elevated urine levels of drugs, medicaments and biological substances\"]]]";
    JArray jsonArray = JsonConvert.DeserializeObject<JArray>(json);
    if (jsonArray.Count > 0)
    {
        foreach (var jVals in jsonArray)
        {
            if (jVals is JArray)
            {
                foreach (var jVal in jVals)
                {
                    if (jVal is JArray)
                    {
                        foreach (var item in jVal)
                        {
                            if ((item as JValue).Value != null)
                            {
                                Response.Write((item as JValue).Value + "<br />");
                            }
                        }
                    }
                    else
                    {
                        if ((jVal as JValue).Value != null)
                        {
                            Response.Write((jVal as JValue).Value + "<br />");
                        }
                    }
                }
            }
            else
            {
                if ((jVals as JValue).Value != null)
                {
                    Response.Write((jVals as JValue).Value + "<br />");
                }
            }
        }
    }
}

VB.Net

Protected Sub Page_Load(ByVal sender As Object, ByVal e As EventArgs) Handles Me.Load
    Dim json = "[1,[""R82.5""],null,[[""R82.5"",""Elevated urine levels of drugs, medicaments and biological substances""]]]"
    Dim jsonArray As JArray = JsonConvert.DeserializeObject(Of JArray)(json)
    If jsonArray.Count > 0 Then
        For Each jVals In jsonArray
            If TypeOf jVals Is JArray Then
                For Each jVal In jVals
                    If TypeOf jVal Is JArray Then
                        For Each item In jVal
                            If (TryCast(item, JValue)).Value IsNot Nothing Then
                                Response.Write((TryCast(item, JValue)).Value & "<br />")
                            End If
                        Next
                    Else
                        If (TryCast(jVal, JValue)).Value IsNot Nothing Then
                            Response.Write((TryCast(jVal, JValue)).Value & "<br />")
                        End If
                    End If
                Next
            Else
                If (TryCast(jVals, JValue)).Value IsNot Nothing Then
                    Response.Write((TryCast(jVals, JValue)).Value & "<br />")
                End If
            End If
        Next
    End If
End Sub

Screenshot