Convert List<Model> to ObservableCollection<ViewModel>

Question

I am considerably new to MVVM implementation. This might sound like a repetitive question but there is nothing that I could find that would help me understand better with my knowledge which is basic. I have a Model class with members as shown here:

public class Model
{
    public string Name { get; set; }
    public int Age { get; set; }
    public List<Model> Children { get; set; }
}

I have wrapped this model class in a view model but with ObservableCollection in place of List.

public class ViewModel
{
    private Model model;
    public ViewModel()
    {
        model = new Model();
    }
    //getters and setters for both Name and Age

    public ObservableCollection<ViewModel> Children
    {
        //how to convert List<Model> to ObservableCollection<ViewModel> here?
    }
}

I definitely do not want to expose my Model class to the view which is why I need to create an ObservableCollection of the VM class. Not sure how to achieve this though. Any help appreciated.

Answer 1

You are probably looking for the following:

public class Model
{
    public string Name { get; set; }
    public int Age { get; set; }
    public List<Model> Children { get; set; }
}
public class ViewModel
{
    public ViewModel(Model m)
    {
        Name = m.Name;
        Age = m.Age;
        Children = new ObservableCollection<ViewModel>(m.Children.Select(md=>new ViewModel(md)));
    }

    public string Name { get; set; }
    public int Age { get; set; }
    public ObservableCollection<ViewModel> Children { get; set; }

    public Model GetModel()
    {
        return new Model()
        {
            Age = Age,
            Name = Name,
            Children = Children.Select(vm=>vm.GetModel()).ToList(),
        };
    }
}

You will note that a lot of that is boilerplate code. But if you do it this way, your model/viewmodel are completely separated, which will save you SO many problems down the line.