Hi,

I am designing a web app which has a combobox (textbox + drop down), much like the Google toolbar where a list of suggestions will show after typing a few characters.

The combobox is meant to suggest member names after a few characters are entered.

Question:

This is AJAX based on asmx script service. Should I have:

1. the Service call the Repository which returns a list of User objects (an Entity with a lot of properties and methods), and then return just an array of names (as DTO) back to the web page?, OR
2. the service call an ad hoc DAL method that returns just a list of names "List (of String)" without involving the Domain Model and any DTO?

Is #2 acceptable in domain driven design? Or should I design some kind of value object around the User entity which contains only Username & Email & First/Last Name (just an example), and work with a Repository for the value object (doesn't sound right to me though... seems like a DTO)?

#1 to me seems just too heavy for this simple operation.

Thanks! I am new to this domain model (used to Transaction Script) so please bear with me.. if this sounds stupid.

Hi Samvan,

I think option two is definately the way to go. Have a look at a popular domain driven design method called Command-Query Responsibility Segregation, it splits all actions down into either a query or a command e,g. Do this or give me this information.The query operations simply return view models (DTOs) straight from the data store.

I also regularly include a readonly reporting or presentation repository that returns simple DTO view models of the domain for senarios like this which I use this directly from the UI. This is much more effective for displaying purposes espically as I am not running any business logic.

Cheers
Scott