Final Review - Tutorial Questions

Question 1

Which .NET attribute is used to decorate a WCF service contract definition? That is, the entire contract, not the individual methods/properties of the contract.

Answer 1

ServiceContract

Question 2

What instance mode causes nothing to be displayed or no change to be visible?

Answer 2

PerCall

Question 3

What instance mode allows the client to see its own changes but not those of any other instance?

Answer 3

PerSession

Question 4

What instance mode allows all clients to have access to the changes made by other instances?

Answer 4

Single

Question 5

What is it absolutely necessary to adjust in the service configuration to maintain a working application when switching to a different binding?

Answer 5

The endpoint address

Question 6

Why apply the ServiceBehavior attribute to a class?

Answer 6

To customize the instancing behavior of the class

Question 7

Which WCF uses PerCall instancing as its default instancing mode?

Answer 7

BasicHttpBinding

Question 8

What is the default instancing mode of NetTcpBinding and NetNamedPipeBinding?

Answer 8

PerSession

Question 9

What is the PerCall instancing mode of all three bindings?

Answer 9

PerCall

Question 10

What is the PerSession instancing mode of BasicHttpBinding?

Answer 10

PerCall

Question 11

What is the PerSession instancing mode of NetTcpBinding and NetNamedPipeBinding?

Answer 11

PerSession

Question 12

What is the Single instancing mode of all three bindings?

Answer 12

Single

Question 13

The following line appears in connectToMessageBoard() in the client’s MainWindow class:

DuplexChannelFactory<IMessageBoard> channel = new DuplexChannelFactory<IMessageBoard>(this, "MessagingService");</IMessageBoard></IMessageBoard>

What is the significance of the argument “this” in the above call?

Answer 13

It’s the client object that implements the callback method

Question 14

Which type of contract is NOT ever implemented by a WCF service?

Answer 14

A callback contract

Question 15

What is the purpose of the WCF callbacks implemented in Tutorial 6?

Answer 15

To allow the service to update all clients in real time with changes to the MessageBoard service object

Question 16

What modification can be made to a WCF service as the final fix to prevent a deadlock that causes an application to become unresponsive or freeze?

Answer 16

The argument IsOneWay = true can be added to the [OperationContract] attributes of void methods in the main Interface and callback interface

Question 17

Once client callbacks are implemented, where can you expect to find the following code:

IUserCallback cb = OperationContect.Current.GetCallbackChannel<IUserCallback>();</IUserCallback>

Answer 17

In the service’s main class (MessageBoard)

Question 18

When defining a service contract, which protocol buffer keyword is used to declare (i.e. prototype) a method call on a service?

Answer 18

rpc

Question 19

When creating a service contract, which main protocol buffer keyword is used to layout the structure of either the input passed into or the output returned from a method call on the service?

Answer 19

message

Question 20

What is the reason for editing a service’s properties associated with a .proto file before implementing the service?

Answer 20

To make sure Visual Studio generates a C# stub class when building the project to implement the service with

Question 21

What Visual Studio project template was used to create the service in Tutorial 7?

Answer 21

ASP.NET Core gRPC Service

Question 22

What were protocol buffers used for in Tutorial 7?

Answer 22

Defining the service contract or interface