Typed Dataset along with Dtos

Question

I have a web application that connects to WCF services for its business logic. I would like to use simple Dto's for transfering data at the WCF boundary for performance and interoperability reasons.

However I have to use typed datasets for data access (ORM or any other option is not available due to political reasons).

Is it a good idea to use Dto's along with typed datasets. Have anyone done this? Is there a recommended pattern? And most importantly is there a library/tool/method to auto generate Dto's from the typed datasets?

Answer 1

I would suggest to use typed DataRow-s, DataTable-s. There's really not much difference between a typed DataRow and a Dto object. Performance wise you have to test it that plain Dto-s will help (I doubt it). As for interoperability, typed DataRow-s are plain classes, so they are as interoperable as Dto objects.

Answer 2

Entity translation pattern comes to mind. http://msdn.microsoft.com/en-us/library/cc304747.aspx
Well, maybe a variation on it.

I had to do something similiar recently, and I just created a another "layer" that translates the data stored in the datarow/datatable etc. into the data contract object. The service layer can call this new layer method with the results from your data-access method as a parameter.

Here's a quick and dirty PSUEDOCODE example:

 public class personTranslator
 {

     public static PersonDataContract TranslateToContract(Datarow personDataRow)
    {
       PersonDataContract resultPerson = new Person;
     resultPerson.FirstName = personDataRow["FirstName"];
     resultPerson.LastName = personDataRow["LastName"];
     .
     .
     [etc.]

     return resultPerson;
    }
 }

SERVICELAYER Class

 public PersonDataContract GetSpecificPerson([Parameters])
 {
     [other setup/validation code...]
    return   PersonTranslator.TranslateToContract(PersonDataAccess.GetPersonRow([Parameters]));
 }