How to Implement Fault Contract in WCF

A Fault Contract is a way to handle an error/exception in WCF. In C# we can handle the error using try and catch blocks at the client-side. The purpose of a Fault Contract is to handle an error by the service class and display in the client-side. Whenever the client makes a call to a service class and an unexpected exception comes such as, SQL Server is not responding, or Divide by zero; in this case, the service class throws an exception to the client using the Fault Contract.

By default when we throw an exception from a service, it will not reach the client. WCF provides the option to handle and convey the error message to the client from a service using a SOAP Fault Contract.

To support SOAP Faults, WCF provides the FaultException class. This class has two forms:

Syntax

The Fault Contract sample demonstrates how to communicate error information from a service to a client. The sample is based on the, with some additional code added to the service to convert an internal exception to a fault.

In ASP.Net, C#, and VB.Net it's very simple to handle an exception just by adding the simple Try & Catch blocks. But when you talk about the WCF Service if an unexpected error occurs (like Server not responding properly and divide by zero) in a WCF Service then the exception details can be passed to the client using a Fault Contract.

FaultContract inherits from the FaultContractAttribute Class.

Now we are going to implement the Fault Contract with database connectivity

Create a table named EMPLOYEE with column names EMP_ID and EMP_NAME. We will create a service to input the user id and get the name of the employee.

Step 2: Open Visual Studio then select "File" -> "New" -> "Project..." -> "WCF" -> "WCF Service Application".