Clone a List(Of Class)
class, clone, icloneable, list, vb.net
Solution
Implementing `IClonable` doesn't mean that it replaces the regular assignment, it will still just copy the reference. And you aren't even copying the items, you are copying the list, which means that you still only have one list, but two references to it.
To use the `Clone` method you have to call it for each item in the list:
rdNew.Hazards = rd.Hazards.Select(Function(x) x.Clone()).Cast(Of Hazard).ToList()
Problem
I've done some reading and cant seem to wrap my head around what the best approach would be to clone a List(of class) in my VB2010 project. I have three classes that are related like so ``` Public Class City 'here are many fields of type string and integer Public Roads As New List(Of Road) End Class Public Class Road 'here are many fields of type string and integer Public Hazards As New List(Of Hazard) End Class Public Class Hazard Implements ICloneable 'here are many fields of type string and integer and double Public Function Clone() As Object Implements System.ICloneable.Clone Return Me.MemberwiseClone End Function End Class ``` So lets say I have a city I'm working on, there are cases where I want to create, as a base one road and its hazards, then add another road but using the prior roads hazards as a starting point and then tweak the fields. ``` Dim rd As New Road 'add road fields dim hz1 as New Hazard 'add hazard fields dim hz2 as New Hazard 'add hazard fields 'add the hazard objects to the road rd.Hazards.Add(hz1) rd.Hazards.Add(hz2) 'add the road to the city myCity.Roads.Add(rd) 'here I want to start a new road based on the old road Dim rdNew As New Road 'copy or clone the hazards from old road rdNew.Hazards = rd.Hazards '<============ 'over-write some of the hazard fields rdNew.Hazards(0).Description = "temp" ``` So I know that copying a class will copy the pointer and not the contents. I used the ICloneable interface in the hazard class but cant say I'm using it right. The Hazards variable is a list of Hazard class. How would i go about cloning that class?