Infinite loop when Json serializing a Collection (VB ASP.NET)

I am trying to use a Web Service to return Json for开发者_运维问答 a Collection of Users from a Database Table. I'm only new to .NET (< 1 week experience), and I don't want to use the UpdatePanel for AJAX. I have tried using the JavaScriptSerializer as well as Json.NET to serialize. Both cases seem to spawn an Infinite Loop.

What am I doing wrong? Is there a better way to do this? I appreciate any suggestions. Thanks.

    Dim myUser As New HagarDB.Users
    myUser.Read()

    'Dim jsSerializer As New System.Web.Script.Serialization.JavaScriptSerializer
    'Dim sbUsers As New System.Text.StringBuilder
    'jsSerializer.Serialize(myUser, sbUsers)

    Dim json = JsonConvert.SerializeObject(myUser, Formatting.Indented)

Thanks to RPM1984 for suggesting DataContractJsonSerializer. Here is the working code:

Public Function GetUsers() As String
    Dim myUser As New HagarDB.Users
    Dim jsonSerializer As New DataContractJsonSerializer(GetType(HagarDB.Users))
    Dim stream As New MemoryStream()

    myUser.Read()
    jsonSerializer.WriteObject(stream, myUser)

    Dim json As String = Encoding.[Default].GetString(stream.ToArray())

    stream.Close()

    Return json


End Function