Introduction:
In this article,i am going to explain about how to handling exceptions in wcf services using fault exception.

Main:

Fault Handling in WCF:
The default behavior for WCF is not to return that exception to the client unless it is thrown as a FaultException
(or inherited subtype) or if a FaultContract is implemented.

See this below simple examble,

Service Code:

using System.Data; using System; using System.Collections.Generic; using System.Text; using System.ServiceModel; using System.Runtime.Serialization;   using System.Threading;   using System.Security; using System.Security.Permissions; using System.Security.Principal;   namespace Products { // Simplified service contract [ServiceContract(Namespace = "http://NetProgrammingHelp.com/2006/09/30", Name = "SimpleProductsService")] public interface ISimpleProductsService { [OperationContract(Name = "ListProducts")] List<string> ListProducts(); }     // WCF service class that implements the service contract public class ProductsServiceImpl : ISimpleProductsService { public List<string> ListProducts() { // Read the configuration information for connecting to the NetPrgHlp database Database dbNetPrgHlp; try { dbNetPrgHlp = DatabaseFactory.CreateDatabase("NetPrgHlpConnection"); } catch (Exception e) { throw new FaultException("Exception reading configuration information for the NetPrgHlp database: " + e.Message, new FaultCode("CreateDatabase")); }   // Retrieve the details of all products by using a DataReader IDataReader productsReader; try { string queryString = @"SELECT ProductNumber FROM Production.Product"; productsReader = dbNetPrgHlp.ExecuteReader(CommandType.Text, queryString); } catch (Exception e) { throw new FaultException("Exception querying the NetPrgHlp database: " + e.Message, new FaultCode("ExecuteReader")); }   // Create and populate a list of products List<string> productsList = new List<string>(); try {   while (productsReader.Read()) { string productNumber = productsReader.GetString(0); productsList.Add(productNumber); } } catch (Exception e) { throw new FaultException("Exception reading product numbers: " + e.Message, new FaultCode("Read/GetString")); }   //Return the list of products return productsList; } } }

Client Code:

using System.ServiceModel; using System; using System.Collections.Generic; using System.Text; using System.ServiceModel.Channels;   namespace ProductsClient { class Program { static void Main(string[] args) { Console.WriteLine("Press ENTER when the service has started"); Console.ReadLine();   try { // Create a default HTTP binding BasicHttpBinding httpBinding = new BasicHttpBinding();   // Create an endpoint EndpointAddress address = new EndpointAddress( "http://localhost:8040/SimpleProductsService/SimpleProductsService.svc");   IChannelFactory<IRequestChannel> factory = httpBinding.BuildChannelFactory<IRequestChannel>(); factory.Open();   IRequestChannel channel = factory.CreateChannel(address); channel.Open();   Message request = Message.CreateMessage(MessageVersion.Soap11, "http://NetPrgHlp.com/2006/09/30/SimpleProductsService/ListProducts");   Message reply = channel.Request(request); Console.Out.WriteLine(reply);   request.Close(); reply.Close(); channel.Close(); factory.Close(); }   catch (Exception e) { Console.WriteLine("Exception: {0}", e.Message); }   Console.WriteLine("Press ENTER to finish"); Console.ReadLine(); } } }

Conclusion:
Hope this helps,
Happy coding.