How to Solve the "WCF Rest Service Interface Error".

Hi Friends,

                In our Project we are working WPF with MVVM using Linq and WCF Rest Services.

We are facing some problem in WCF Rest Service .We are creating Interface like below,

[OperationContract]

[WebGet(ResponseFormat = WebMessageFormat.Json, BodyStyle = WebMessageBodyStyle.WrappedRequest)]

[FaultContract(typeof(DEErrorProvider))]

Tuple, DEErrorProvider> getEmploteeList();

In above Mark Line in ResponseFormat if we are using Json means we are getting the below Error

"The underlying connection was closed: The connection was closed unexpectedly."

If we use Xml in ResponesFormat it is working fine. But we need JSON Format.

In BL we are creating Method like below.

      public Tuple<ObservableCollection<DEEmployee>, DEErrorProvider> getEmploteeList ()

        {

            ContactCollection = new ObservableCollection<DEEmployeet>();

            ErrorCollection = new DEErrorProvider();

            try

            {

                using (EmployeeEntities EmpEntity = new EmployeeEntities())

                {

                    Here we are creating our Business Logic with Linq Query Collection.

                }

                ErrorCollection.ErrorResult = true;

            }

             catch (Exception ex)

            {

                ErrorCollection.ErrorMessage = ex.Message;

                ErrorCollection.ErrorTrace = ex.StackTrace;

                ErrorCollection.ErrorResult = false;

            }

            return new Tuple<ObservableCollection<DEEmployee>, DEErrorProvider>(EmployeeCollection, ErrorCollection);

        }

Please help me to solve this problem.