单项选择题
A. Add the KnownType attribute to the data contract. Set a default value in each of the data member declarations.
B. Add the KnownType attribute to the data contract. Set the Order property of each data member to unique integer value.
C. Set the EmitDefaultValue property of each data member to false.
D. Set the lsRequired property of each data member to true.
单项选择题 You are developing a data contract for a Windows Communication Foundation (WCF) service. The data in the data contract must participate in round trips. Strict schema validity is not required. You need to ensure that the contract is forward-compatible and allows new data members to be added to it. Which interface should you implement in the data contract class?（）
单项选择题 You are creating a Windows Communication Foundation (WCF) service that is implemented as follows. (Line numbers are included for reference only.) 01 [ServiceContract] 02 [ServiceBehavior(IncludeExceptionDetailsInFaults = true)] 03 public class OrderService 04 { 05 [OperationContract] 06 public void SubmitOrder(Order anOrder) 07 { 08 try 09 { 10 ... 11 } 12 catch(DivideByZeroException ex) 13 { 14 ... 15 } 16 } 17 } You need to ensure that the stack trace details of the exception are not included in the error information sent to the client. What should you do?（）