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The ABC of Windows Communication Foundation

“ABC” is the WCF mantra. “ABC” is the key to understanding how a WCF service endpoint is composed. Think Ernie, Bert, Cookie Monster or Big Bird. Remember “ABC”.

• “A” stands for Address: Where is the service?
• “B” stands for Binding: How do I talk to the service?
• “C” stands for Contract: What can the service do for me?

Web services zealots who read Web Service Description Language (WSDL) descriptions at the breakfast table will easily recognize these three concepts as the three levels of abstraction expressed in WSDL. So if you live in a world full of angle brackets, you can look at it this way:

• “A” stands for Address—as expressed in the wsdl:service section and links wsdl:binding to a concrete service endpoint address.
• “B” stands for Binding—as expressed in the wsdl:binding section and binds a wsdl:portType contract description to a concrete transport, an envelope format and associated policies.
• “C” stands for Contract—as expressed in the wsdl:portType, wsdl:message and wsdl:type sections and describes types, messages, message exchange patterns and operations.

“ABC” means that writing (and configuring) a WCF service is always a three-step process:

• You define a contract and implement it on a service
• You choose or define a service binding that selects a transport along with quality of service, security and other options
• You deploy an endpoint for the contract by binding it (using the binding definition, hence the name) to a network address.

A contract is an agreement between two parties. It defines how a client should communicate with your service. In other words a contract is a platform and standard way of describing what the service does. There are the following four types of contracts in WCF Service Contract :

• Service contract
• Data Contract
• Operation Contract
• Fault Contract
• Message Contract

we've already used Data Contract and Operation Contract.

Follow this tutorial for more details

Follow this tutorial for more details

In WCF (Windows Communication Foundation), we will not expose exception directly to client if it occurs at service level. Fault Contract is used to return error details to the other party i.e. client.

DataContract has limited control over the SOAP message and all that control is related to contents inside body of the SOAP message. But there are scenarios, when we need more control over SOAP message. So, MessageContract is the answer in such cases.

Create a simple calculator service with Add operation which throw general exception and send exception information from service to client with FaultException.

Follow this tutorial for more details

Follow this tutorial for more details

Introduction to Building Windows Communication Foundation Services