使用实体框架4克隆对象

我找到了下面的代码,它应该克隆一个实体。在我的例子中,我为一个人准备了一个表格,并且有多个垂直线用于电话号码、电子邮件等。当我尝试克隆一个个人实体时,代码似乎可以正常工作。但是,当我试图将对象添加到我的表中时,会出现以下错误。

“无法添加或附加对象,因为其EntityReference的EntityKey属性值与此对象的EntityKey不匹配。”

我不太确定要改变什么才能使这项工作发挥作用。

private static T DataContractSerialization<T>(T obj)
        {
            DataContractSerializer dcSer = new DataContractSerializer(obj.GetType());
            MemoryStream memoryStream = new MemoryStream();

            dcSer.WriteObject(memoryStream, obj);
            memoryStream.Position = 0;

            T newObject = (T)dcSer.ReadObject(memoryStream);
            return newObject;
        }

以下是我使用代码的方式。

public static void CopyData(int sourcecompanyid)
        {
            var rUtil = new CREntities();
            rUtil.Connection.Open();

            using (var r = new CREntities())
            {

                var candidates = r.Candidates.Include("Phones").Include("Emails").Where(c => c.companyId == sourcecompanyid);

                foreach (var candidate in candidates)
                {
                    ObjectParameter newcandid = new ObjectParameter("newcandid", typeof(string));

                    Candidate newcand = DataContractSerialization<Candidate>(candidate);

                    rUtil.GetNextCandId(newcandid);

                    newcand.CandID = newcandid.Value.ToString();

                    foreach (var phone in newcand.Phones)
                        phone.CandID = newcand.CandID;

                    foreach (var email in newcand.Emails)
                        email.CandID = newcand.CandID;

                    rUtil.Candidates.AddObject(newcand);
                    rUtil.SaveChanges();
                }
            }
            rUtil.Connection.Close();
            rUtil.Dispose();
        }

        private static T DataContractSerialization<T>(T obj)
        {
            DataContractSerializer dcSer = new DataContractSerializer(obj.GetType());
            MemoryStream memoryStream = new MemoryStream();

            dcSer.WriteObject(memoryStream, obj);
            memoryStream.Position = 0;

            T newObject = (T)dcSer.ReadObject(memoryStream);
            return newObject;
        }