WCF Interview Questions and Answers
WCF is an abbreviated form of Windows Communication Foundation, which is a unified communication framework developed for distributed applications. In other words, it is a unified API for services and clients for the purpose of sending information between each other. The main characteristics of WCF are SOA, extensibility, and interoperability. This is the prime and most important information which is often asked during WCF Interview Questions. Given below are the commonly asked interview questions that will help you to crack WCF interviews. SOA (Service-Oriented Architecture) is an approach to protocol-independent, loosely coupled and standard-based distributed computing where software resources that are available over the network are considered as a service. Likewise, interoperability is also a prime feature of WCF, as it implements a number of WS-*standards. Even, WCF client/server platform configures itself to interoperate with REST, ATOM-feeds, Plain XML or JSON messages. Therefore, WCF provides a secure, reliable and transacted messaging platform along with interoperability.
Most Frequently Asked WCF Interview Questions
In general exception handling is one of the features of object programming language and it is an error that accurate which occurs runtime. Exception handling is a technique which is used to handle runtime errors. In order to handle expectations try, catch and finally block are used. Id the expiration handling technique is unable to handle the runtime error then the execution of the application automatically terminated.
There are three ways of handling exception in WCF
- Faultexception
- IErrorHandler
- returnUnknownExceptionAsFaults
KnownTypeAttribute is an attribute which allows specifying the types that should be included during the process of deserialization. The users are using KnownTypeAttribute only when they want to accept the service and return an inherited type.
In practice, HTTP binding is suitable for communicating securely with ASP.NET Web service (ASMX) based services. In addition to this, WCF services use HTTP binding service in order to transport text/XML ass a default message.
In order to create HTTP binding in WCF following steps need to be performed
- Create WCF HttpBinding project
- Open Visual Studio
- Create a New Project from the start page
- Go to File menu, select New and then click on the project
- A dialog box will pop up over the display screen
- With the help of installed templates select C#
- Inside C# select WCF and then select WCF service application
Yes, we have method overloading in WCF. In the general method, overloading is one of the optimal features that allow the users to create multiple methods with the same name but each method performs different functionality from each there in the context of input and output. In other words, method overloading methods name will be the same but the parameters differ from each other. Method overloading is used during compile time polymorphism.
There are different type of binding in WCF namely-
- BasicHttpBinding
- WSHttpBinding
- WSDualHttpBinding
- WSFederationHttpBinding
- NetTcpBinding
- NetNamedPipeBinding
- NetMsmqBinding
- NetPeerTcpBinding
WCF service handles new about 40 requests and WCF handles each request with the help of call which implies that one instance of WCF service will be created for each request.
Some of the advantages and disadvantages of WCF web services are listed below-
Advantages
- Interoperability (the single platform is used in order to exchange information using different routing protocols)
- Security and reliability (Provided with auditing, authentication, confidentiality, integrity features)
- Supports Ajax, REST and Plain OML
If you really want to crack the WCF interview than don’t miss to read our WCF Interview Questions.
Disadvantages
- High level of abstraction
- Lost of a pre-used set of libraries
- Unclear to understand web services in RoR.