Return list of entities from web service

Question

I use an Entity Framework (edmx file) for my model, and I'm using WCF to access my model. When try to return list of an entity data model (example table object), i get an error:

The server did not provide a meaningful reply; this might be caused by a contract mismatch, a premature session shutdown or an internal server error.

Here is my WCF code. IService.cs:

[ServiceContract(CallbackContract = typeof(IPesananCallBack), SessionMode = SessionMode.Required)]
public interface IPelayanWebService
{
   [OperationContract]
   List<table> GetAllTables();
}

Service.cs:

public List<table> GetAllTables()
{
    TableModel model = new TableModel();
    return model.GetAllTables();
}

My code in model:

public List<table> GetAllTables()
{
    using (restoicdbEntities ent = new restoicdbEntities())
    {
        return ent.table.ToList();
    }
}

in my client, I just call that function, and the error occured. Do I have to create my own data contract? Is there anyway to generate the datacontract from the edmx?

Update: This is the generated code from Entity Framework:

[EdmEntityTypeAttribute(NamespaceName="restoicdbModel", Name="table")]
[Serializable]
[DataContractAttribute(IsReference=true)]
public partial class table: EntityObject
{
    [EdmScalarPropertyAttribute(EntityKeyProperty=true, IsNullable=false)]
    [DataMemberAttribute()]
    public global::System.Int32 ID_TABLE
    {
        get
        {
            return _ID_TABLE;
        }
        set
        {
            if (_ID_TABLE != value)
            {
                OnID_TABLEChanging(value);
                ReportPropertyChanging("ID_TABLE");
                ID_TABLE = StructuralObject.SetValidValue(value);
                ReportPropertyChanged("ID_TABLE");
                OnID_TABLEChanged();
            }
        }
    }
    private global::System.Int32 ID_TABLE;
    partial void OnID_TABLEChanging(global::System.Int32 value);
    partial void OnID_TABLEChanged();
}

Answer 1

After reading the link provided by Steve Wilkes, WCF, Entity Framework & Data Contracts , it looks like it is not good to pass entity object from web service. So I have to create my own Data Transfer Object which is a mapping from the entity object, then pass it from the web service.