Using vb.net to parse through json code with exception - json

Question

I am trying to use vb.net windows forms application to parse through some JSON code. My code builds just fine and compiles, but the moment I click on my button, I get this exception:
Newtonsoft.Json.JsonReaderException: 'Error parsing NaN value. Path '', line 1, position 1.'
The exception is pointing to this line at the end of my code:
For Each item As JObject In JArray.Parse(jsonObjects.SelectTokens("items").ToString)
I have tried to solve it, but I don't know how to anymore. Here is my code:
Imports Newtonsoft.Json
Imports Newtonsoft.Json.Linq
Public Class Form1
Private Sub Button1_Click(sender As Object, e As EventArgs) Handles Button1.Click
Dim jsonString As String = "{""id"":1, ""name"":""tom"",
""items"":[
{""name"":""apple"", ""count"":1 },
{""name"":""milk"", ""count"":2 }
]
}"
Dim jsonObjects As JObject = JObject.Parse(jsonString)
Console.WriteLine("id:" & jsonObjects.SelectTokens("id").ToString)
Console.WriteLine("name:" & jsonObjects.SelectTokens("name").ToString)
Console.WriteLine("items:" & jsonObjects.SelectTokens("items").ToString)
'Dim jsonArray As JArray = JArray.Parse(jsonObjects.SelectTokens("items").ToString)
For Each item As JObject In JArray.Parse(jsonObjects.SelectTokens("items").ToString)
Console.WriteLine("item:" & item.SelectTokens("name").ToString)
Next
End Sub
End Class

Answer 1

I am trying to ... parse through some JSON
Before you get to the exception at the loop start, this wont result in anything very useful:
Console.WriteLine("id:" & jsonObjects.SelectTokens("id").ToString)
SelectTokens returns an IEnumerable(Of Newtonsoft.Json.Linq.JToken). Trying to display it with ToString will just result in:
Newtonsoft.Json.Linq.JsonPath.FieldFilter+<ExecuteFilter>d__0
If you want several items from throughout the JSON it would probably be easier to deserialize it to a NET object or collection, but thats not what you asked. This will list the items that Tom has:
Dim jobj = JObject.Parse(Candyjson)
' print the Id, name and how many items there are
Console.WriteLine("Id: {0} Name: {1} has {2} Items", jobj("id"), jobj("name"),
jobj("items").Count)
' print each item name and how many there are
For n As Int32 = 0 To jobj("items").Count - 1
Console.WriteLine("Item: {0}, Count: {1}",
jobj("items")(n)("name"),
jobj("items")(n)("count")
)
Next
Results:
Id: 1 Name: tom has 2 Items
Item: apple, Count: 1
Item: milk, Count: 2
One you parse the JSON, the resulting JObject will contains various other things depending on what is in the JSON. If you set a breakpoint and examine jobj, the result will look much the same as your JSON (string), but it is in a form you can query: