Question

Is it possible to project every property of an object and add more, without specifically listing them all. For instance, instead of doing this:

   var projection = from e in context.entities
                    select new QuestionnaireVersionExtended
                    {
                        Id = e.Id,
                        Version = e.Version,
                        CreationDate = e.CreationDate,
                         ... 
                         many more properties
                         ...
                        NumberOfItems = (e.Children.Count())
                    };

Can we do something like this:

   var projection = from e in context.entities
                    select new QuestionnaireVersionExtended
                    {
                        e,
                        NumberOfItems = (e.Children.Count())
                    };

Where it will take every property from e with the same name, and add the “NumberOfItems” property onto that?

Answer 1

No this is not possible. The select clause of a LINQ expression allows for normal C# expressions which produce a value. There is no C# construct which will create an object via an object initializer in a template style manner like this. You’ll need to either list the properties or use an explicit constructor.