Best way to create instance of child object from parent object

user_1727038 0
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I'm creating a child object from a parent object. So the scenario is that I have an object and a child object which adds a distance property for scenarios where I want to search. I've chosen to use inheritance as my UI works equivalently with either a search object or a list of objects not the result of a location search. So in this case inheritance seems a sensible choice.

As present I need to generate a new object MyObjectSearch from an instance of MyObject. At present I'm doing this in the constructor manually by setting properties one by one. I could use reflection but this would be slow. Is there a better way of achieving this kind of object enhancement?

Hopefully my code below illustrates the scenario.

public class MyObject {

    // Some properties and a location.
}

public class MyObjectSearch : MyObject {

    public double Distance { get; set; }
    
    public MyObjectSearch(MyObject obj) {
         base.Prop1 = obj.Prop1;
         base.Prop2 = obj.Prop2;
    }
}

And my search function:

public List<MyObjectSearch> DoSearch(Location loc) { 
  var myObjectSearchList = new List<MyObjectSearch>();       

   foreach (var object in myObjectList) {
       var distance = getDistance();
       var myObjectSearch = new MyObjectSearch(object);
       myObjectSearch.Distance = distance;
       myObjectSearchList.add(myObjectSearch);
   } 
   return myObjectSearchList;
}
objectinstantiation inheritance .net c#
8 Answers

I first came accros this question when I was looking for doing this. If you are able to work with C# 9 and record-classes. You only have to create a new constructor in the sub-class taking in a base class object and hand it over to the subclass:

public record MyObject {
  ...
}

public record MyObjectSearch {
 public MyObjectSearch(MyObject parent) : base(parent) { }
 ...
}

Then you can create the child object like this:

MyObject parent = new();
MyObjectSearch m = new MyObjectSearch(parentObj) { Distance = 1.1};

Credits to https://stackoverflow.com/a/64573044/2582968

user_25829680
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