从AJAX请求中反序列化Webmethod中的JSON

我有一个javascript内置的JSON对象，我想传递到一个ajax请求到VB。Net WebMethod并对其进行反序列化。我使用Newtonsoft JSON来反序列化对象。对象似乎被传递了但当我试图将其反序列化为对象时，我得到了这个错误:Error converting value "myid" to type 'AnID.RF.MyIDProfile'.

下面是我使用的javascript代码:

function test() {
    var testdata;
    testdata = "{'data':{'ses':'','profile':{'myid':'myid','username':'User','firstName':'adf','lastName':'lastname','languagePreference':'en'}}}";
    $.ajax({
        type: "POST",
        url: "default.aspx/Foo",
        data: testdata,
        contentType: "application/json; charset=utf-8",
        dataType: "json",
        beforeSend: function() {
        },
        success: function(data) {
            if (data != "") {
                alert(data.d);
            }
        },
        error: function(jqXHR, textStatus, errorThrown) {
            alert(errorThrown);
        }
    })
}

服务器端代码:

           <System.Web.Services.WebMethod()> _
        Public Shared Function Foo(ByVal data As Object) As String
            Dim jO As JObject = JObject.FromObject(data)
            Dim sMessage As String = "y"
            Try
                Dim results As IList(Of JToken) = jO("profile").Children().ToList()
                Dim searchResults As IList(Of RF.MyIDProfile) = New List(Of RF.MyIDProfile)()
                For Each result As JToken In results
                    Dim searchResult As RF.MyIDProfile = JsonConvert.DeserializeObject(Of RF.MyIDProfile)(result.ToString())
                    searchResults.Add(searchResult)
                Next
                Dim stest As String = jO.SelectToken("profile.myid").ToString
            Catch ex As Exception
                sMessage = "e"
            End Try

            Return sMessage
        End Function
        Namespace RF
            Public Class MyIDProfile
                Private sMYID As String
                Private sUSERName As String
                Private sPrefix As String
                Private sFirstName As String
                Private sLastName As String
                Private slanguagePreference As String
                Public Property myid() As String
                    Get
                        Return sMYID
                    End Get
                    Set(ByVal value As String)
                        sMYID = value
                    End Set
                End Property

                Public Property username() As String
                    Get
                        Return sUSERName
                    End Get
                    Set(ByVal value As String)
                        sUSERName = value
                    End Set
                End Property
                Public Property firstName() As String
                    Get
                        Return sFirstName
                    End Get
                    Set(ByVal value As String)
                        sFirstName = value
                    End Set
                End Property
                Public Property lastName() As String
                    Get
                        Return sLastName
                    End Get
                    Set(ByVal value As String)
                        sLastName = value
                    End Set
                End Property
                Public Property languagePreference() As String
                    Get
                        Return slanguagePreference
                    End Get
                    Set(ByVal value As String)
                        slanguagePreference = value
                    End Set
                End Property
            End Class
        End Namespace

如果我使用SelectToken("profile.myid")，我能够获得没有问题的值。我不确定我可能做错了什么，导致这个错误。有人能看一下吗?