Create object based on another.

whelzer posted on Monday, June 08, 2009

Small issue (I think)

I've got Object A - inherited from BB.

I've also got Object B also inherited from BB.

I need to create an instance of Object A based on the values from Object B. (they're are approx 90 properties in total).

Should I do pass in the entire object B to object A, eg:

public shared GetObjectA_basedOnB(byval b as ObjectB)

call a DP_fetch which basically transfers the values:

ObjectA.prop1 = ObjectB.prop1
ObjectA.prop2 = ObjectB.prop2

end sub

Or

Just pass in the ObjectB Id and let it do a fetch/find

public shared GetObjectA_basedOnB(byval bID as Integer)

Call a DP_Fetch which does this..

Dim b as objectB = objectB.GetB(bID)

then the property transfer.

End sub

Very little difference really but I'd to know whats the practice - I could use also DTO but it seems like a waste. I'm using VB/Winforms if that helps..

triplea replied on Monday, June 08, 2009

I would use your first approach but call DP_Create running locally.

I wouldn't use the second approach, it looks less readable since you perform a fetch on object A while really you are performing that action on object B and then copying the values.

JoeFallon1 replied on Monday, June 08, 2009

You should try out the DataMapper class to copy the values from one BO to another. It is quite flexible and it also has an excluded properties list.
Joe

whelzer replied on Monday, June 08, 2009

Just checked out the DataMapper p285 2005 VB Book. Superb piece of functionality!
Don't know why I never came across it before. Glad I didn't write all 90 lines out...