ContactBook Part 9 - WindowsDialogService

    public class WindowDialogService : IDialogService
    {
        public string OpenFile(string filter)
        {
            var dialog = new OpenFileDialog();

            if(dialog.ShowDialog() == true)
            {
                return dialog.FileName;
            }

            return null;
        }

        public void ShowMessageBox(string message)
        {
            throw new NotImplementedException();
        }
    }