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Table of contents
1.
Introduction
2.
WCF Interview Questions for Freshers
2.1.
1.What is WCF?
2.2.
2. What are the main components used in WCF?
2.3.
3. What is the "Address" property of the endpoint in WCF?
2.4.
4. What is the service in WCF?
2.5.
5. What are the various instance modes in WCF?
2.6.
6. What are the various benefits or advantages of WCF Technology? 
2.7.
7. Explain what the difference between ASMX web services and WCF is.
2.8.
8. What is WCF ABC?
2.9.
9. How many types of contracts does WCF define?
2.10.
10. What are the features and advantages of WCF?
2.11.
11. What are standard Endpoints?
2.12.
12. Explain the fundamentals of WCF.
2.13.
13. Explain the architecture of WCF.
3.
WCF Interview Questions for Experienced
3.1.
14. What are the components of the WCF application?
3.2.
15. What are the various isolation levels provided in WCF?
3.3.
16. Explain about SOA.
3.4.
17. What do you mean by transactions in WCF?
3.5.
18. What do you mean by WCF Binding?
3.6.
19. What are the various binding types available in WCF?
3.7.
21. What do you mean by Data Contract Serializer?
3.8.
22. What do you mean by the term impersonation?
3.9.
23. What are the different transport schemas that are supported by WCF?
3.10.
24. What do you mean by MSMQ?
3.11.
25. What do you mean by Streaming?
4.
Conclusion
Last Updated: Mar 27, 2024

WCF interview questions

Author Alok Pandey
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Introduction

WCF is an abbreviation for Windows Communication Foundation. It is a service-oriented application framework and is mostly employed in developing a distributed and interoperable application. You can communicate data as asynchronous messages from one service endpoint to another using WCF. WCF Applications first appeared in the.Net 3.0 Framework.

WCF interview questions

WCF is built entirely on the.NET framework. It is typically implemented as a set of classes in the.NET framework corresponding to the CLR. WCF, on the other hand, enables.NET application developers to create service-oriented applications. It addresses the issue of interoperability in distributed applications using. NET. To communicate with the server, the WCF client employs the Simple Object Access Protocol (SOAP). The operating system, hardware, and programming platform are unimportant to the client and server, and communication occurs at a high degree of abstraction.

WCF Interview Questions for Freshers

1.What is WCF?

WCF is a service-oriented application framework and is mostly employed in developing a distributed and interoperable application. You can communicate data as asynchronous messages from one service endpoint to another using WCF. A service client can be an endpoint that requests data from a service endpoint. It allows you to develop more secure, flexible services without changing code. It also has built-in logging functionality. It enables and disables logging through settings.
 

2. What are the main components used in WCF?

There are mainly three essential components in WCF:

  1. Service class
     
  2. Endpoint
     
  3. Hosting Environment
     

3. What is the "Address" property of the endpoint in WCF?

The "Address" property is a service-level endpoint property. This field is used to indicate the service's location.
 

4. What is the service in WCF?

A service is a set of functionality that is exposed to the outside world. Service orientation (SO) is a general term for a set of concepts and best practices for developing service-oriented applications.
 

5. What are the various instance modes in WCF?

The different instance modes in WCF are the following:

  1. Per Call
  2. Singleton
  3. Per Session
    Click here to read about Power Apps Interview Questions here. 
     

6. What are the various benefits or advantages of WCF Technology? 

There are the following advantages of WCF Technology:
 

  1. The framework can be customized to work with either SOAP or RSS.
     
  2. This is a common communication technology that performs better when compared to other Microsoft specs.
     
  3. This architecture is appropriate for a secure connection, data transmission, and even speed optimization. It exchanges data in binary format to reduce latency.
     
  4. This distributed management solution is suitable for practically all WCF-based applications.
     

7. Explain what the difference between ASMX web services and WCF is.

The primary distinction between WCF and ASMX or ASP.NET web services is that ASMX is meant to transmit and receive messages only via SOAP over HTTP. In comparison, the WCF can send messages in any format via any transport protocol.
 

8. What is WCF ABC?

In WCF ABC stands for Address, Billing, and Contract.

WCF ABC

9. How many types of contracts does WCF define?

There are mainly four types of contracts does WCF defines as follows:

  • Contracts for Services
    The ServiceContract attribute connects a CLR interface (or inferred interface, as we'll learn later) to a technology-independent service contract. The ServiceContract property exposes a CLR interface (or a class) as a WCF contract, regardless of the visibility.
     
  • Data Contracts
    The metadata descriptions of the data types that the service utilizes. This allows people to interact with the service. The data types can be used anywhere in a message, such as arguments or return types. There is no need to employ data contracts explicitly if the service just uses simple types.
     
  • Fault Contracts
    Errors that can be returned to the caller can be associated with a service action.
     
  • Message Contracts
    Describes a message's format. It specifies, whether message elements should be placed in headers or the body, what level of security should be given to which message elements, and so on.

10. What are the features and advantages of WCF?

The features of WCF are as follows:

  • Service Orientation
     
  • Interoperability
     
  • Multiple Message Patterns
     
  • Service Metadata
     
  • Reliable and Queued Messages
     
  • Data Contracts
     
  • Security
     
  • Multiple modes of transport and Encodings
     
  • Durable Messages
     
  • Transactions
     
  • Extensibility
     
  • AJAX and REST Support

    Advantages of WCF:
     
  • Service Oriented
     
  • Location Independent
     
  • Language Independent
     
  • It can control concurrency
     
  • Support Multiple operations
     
  • It can maintain state
     
  • Platform Independent
     
  • It can be hosted on IIS, WAS, Self-hosting, and Windows services.

11. What are standard Endpoints?

WCF provides a collection of pre-defined endpoints referred to as Standard Endpoints for metadata sharing, discovery, and web services. The standard endpoints can be configured using a config file or programmatically. The following is a list of standard endpoints:

  • mexEndpoint
     
  • webHttpEndpoint
     
  • webScriptEndpoint
     
  • workflowControlEndpoin
     
  • announcementEndpoint
     
  • discoveryEndpoint
     
  • udpAnnouncementEndpoint
     
  • udpDiscoveryEndpoint

12. Explain the fundamentals of WCF.

The Windows Communication Foundation (WCF) is a framework for developing service-oriented applications that allow us to transfer asynchronous messages/data from one service endpoint to another.

WCF is a runtime and API set for building systems that deliver messages between services and clients. The same infrastructure and APIs are used to develop apps that connect with other programs on the same computer system or on a system hosted by another firm and accessible over the Internet.

The WCF fundamentals are as follows:

  • Unification 
    1. COM+ Services
    2. Web Services
    3. .NET Remoting
    4. Microsoft Message Queuing 
       
  • Interoperability
  • Service Orientation

13. Explain the architecture of WCF.

A new service-oriented programming approach is available to developers in four main tiers. The following layers make up the WCF architecture.

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WCF Interview Questions for Experienced

14. What are the components of the WCF application?

WCF application mainly  consists of 3 components:

  • WCF Service
     
  • WCF Service Host
     
  • WCF service client

15. What are the various isolation levels provided in WCF?

The various isolation levels provided in WCF are given below:

  • Read Uncommitted.
     
  • Read Committed.
     
  • Repeated read.

16. Explain about SOA.

It stands for "Service-oriented Architecture," which is a method of building software.

17. What do you mean by transactions in WCF?

A transaction in WCF is a collection of actions that correspond to specific criteria known as ACID. In the event of a single failure, the entire system crashes. When an order is placed online, a transaction happens. Transactions are classified into two types: atomic and long-running.

18. What do you mean by WCF Binding?

WCF bindings are made up of a variety of binding components that define how the service and client will communicate. Bindings are used by clients based on their requirements. As a result, binding is essentially a mechanism for clients and services to interact in line with the demands of the client. It supports a number of protocol types for communication with clients, as well as several encodings for data transmission over the internet.

19. What are the various binding types available in WCF?

There are different kinds of binding available in WCF, including:
 

  • NetPeerTcp Binding 
     
  • NetTcp Binding 
     
  • WSHttp Binding 
     
  • Basic HTTP Binding 
     
  • WSDualHttp Binding
     
  • MsmqIntegration Binding
     
  • NetMsmq Binding 
     
  • NetMsmq Binding 
     
  • NetNamedPipeBinding 
     
  • WSFederationHttp Binding 

21. What do you mean by Data Contract Serializer?

WCF's default serializer is the DataContractSerializer class. This serializer may be used for additional serialization tasks. We may explicitly build a data contract using the DataContractAttribute and DataMemberAttribute properties.

Data Contract Serializer

22. What do you mean by the term impersonation?

Impersonation is a method used by services to limit client access to the resources of a service domain. Impersonation is disabled by default in WCF, and services are accessible via the WCF service's process identity.

23. What are the different transport schemas that are supported by WCF?

Different transport schemas supported by WCF include: 

  1. HTTP
  2. TCP
  3. Peer network
  4. IPC
  5. MSMQ

24. What do you mean by MSMQ?

MSMQ (Microsoft Messaging Queue) is essentially an asynchronous communication system. MSMQ can also communicate with other processes. When two processes want to interact in a "Fire and Forget" fashion, MSMQ comes in handy. MSMQ was created by Microsoft and is included in the Windows operating system. It enables communication across diverse networks and systems that may occasionally go offline.

25. What do you mean by Streaming?

WCF supports the transfer of images,.pdf files, and big documents. Streaming is the most effective and widely used way of accomplishing this. Message streaming allows the recipient (either a client or a service) to begin processing the message before it has received the whole message. Because streamed transfers eliminate the need to store big memory buffers in the background, scalability improves.

Conclusion

In this article, we have extensively discussed the WCF interview questions and answer series covering the various-level WCF interview questions. If you would like to learn more, check out our articles on
 

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