单项选择题 A Windows Communication Foundation (WCF) service is deployed with netTcpBinding. This service uses a duplex message exchange pattern.You are developing the next version of the WCF service. You discover that your companys hardware load balancer performs correctly only for WCF services that use HTTP. You need to ensure that your service works with the load balancer. What should you do?（）

多项选择题 You are developing a Windows Communication Foundation (WCF) service to provide shopping cart support. ASP.NET compatibility mode is not enabled. The shopping cart information must be retained across user visits to the store until the user explicitly empties the cart or submits the cart contents to order.You need to implement the service as a DurableService.Which two actions should you perform? （）(Each correct answer presents part of the solution. Choose two.)

单项选择题 You are developing a Windows Communication Foundation (WCF) service.One of the service operations contains the following code.private static int counter = 0;[OperationContract]public void IncrementCount(){ counter++;}You need to set a service behavior that prevents two or more threads from incrementing the counter variable at the same time. Which code segment should you use to set the service behavior?（）