Data Transfer Object (DTO)

/*By Jiangong SUN*/

DTO pattern is used to "transfer data" using objects

DTO vs. VO(Value Objects)

Value Object must be immutable, serializable and it’s content must be publicly accessible.
A Value Object can only be changed and persisted by the creation of a new Value Object based on the values of the original Value Object obtained.

A Transfer Object while similar in most respects is mutable. In addition there is a reasonable expectation that the Transfer Object will be persisted if it is returned to the originating layer.


Usage of DTO: It can get attributes from differenct objects and consists as a new object for particular use.

In my project i've used it to fill in the asp .net repeater.

Code example:

public class UniverseDTO    {        public string ImagePath { get; set; }        public string Code { get; set; }        public string Label { get; set; }        public int Order { get; set; }        public List<SubUniverseDTO> SubUniverses { get; set; }    }

 List<UniverseDTO> universes = (from universe in UniversesService.GetUniverses()               select new UniverseDTO               {                 Code = universe.code,                 Label = universe.label,                 Order = universe.order,                 ImagePath = newpath,                 SubUniverses = UniversesService.GetSubUniverses(universe.code)                }).OrderBy(x => x.Order).ToList();

Reference :
http://rrees.wordpress.com/2007/05/13/transfer-objects-versus-value-objects/
http://stackoverflow.com/questions/725348/poco-vs-dto
http://martinfowler.com/eaaCatalog/dataTransferObject.html
http://www.adam-bien.com/roller/abien/entry/value_object_vs_data_transfer
http://www.adam-bien.com/roller/abien/entry/how_evil_are_actually_data
http://stackoverflow.com/questions/1612334/difference-between-dto-vo-pojo-javabeans