WCF中的异常处理(1)

[ServiceContract(SessionMode = SessionMode.Allowed)]
public interface IDocumentsExplorerService
{
[OperationContract]        
DocumentList FetchDocuments(string homeDir);
}
[ServiceBehavior(InstanceContextMode=InstanceContextMode.Single)]
public class DocumentsExplorerService : IDocumentsExplorerService,IDisposable
{
public DocumentList FetchDocuments(string homeDir)
{
//Some Codes

if (Directory.Exists(homeDir))
{
//Fetch documents according to homedir
}
else
{
throw new DirectoryNotFoundException(
string.Format("Directory {0} is not found.",homeDir));
}
}
public void Dispose()
{            
Console.WriteLine("The service had been disposed.");
}
}

catch (DirectoryNotFoundException ex)
{
//handle the exception;
}

catch (FaultException ex)
{
//handle the exception;
}
catch (Exception ex)
{
//handle the exception;
}

[ServiceContract(SessionMode = SessionMode.Allowed)]
public interface IDocumentsExplorerService
{
[OperationContract]
[FaultContract(typeof(DirectoryNotFoundException))]
DocumentList FetchDocuments(string homeDir);
}