//Model
public sealed class Model {
  public string A {get; set;}
}

public sealed class Models : ObservableCollection<Model> {}

//ViewModel
public sealed class ViewModel {
  public ViewModel() {
    this.Items = new Models();
    this.MyCommand = new DelegateCommand<RequestItem>(OnMyCommand);
  }

  public void OnMyCommand(Model item){
   
  }

  public Models Items {get; private set;}

  public ICommand MyCommand {get; private set;}
}

//View
public sealed class View {
  public View() {
    InitializeComponent();
    this.DataContext = new ViewModel();
  }
}