using System.Collections.ObjectModel;
using System.ComponentModel;

namespace BlogSamples.ViewModels
{
    public class MainPageViewModel : INotifyPropertyChanged
    {
        //...

        public ObservableCollection<string> RandomStrings { get; private set; }

        public string SelectedString
        {
// ... property impl not shown for brevity
        }

        public MainPageViewModel()
        {
            RandomStrings = new ObservableCollection<string>();
            for (int i = 65; i < 98; i++)
            {
                RandomStrings.Add(((char)i).ToString().ToUpper());
            }
        }
    }
}