WPF

private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            DataTable _dtPayments = GetPayments(_intID);
                DataView defaultView = _dtPayments.DefaultView;

                dgPayments.ItemsSource = defaultView;
        }

public class clsPaymentViewModel : INotifyPropertyChanged
    {
        clsPaymentManager _PaymentManager = new clsPaymentManager();

        public clsPaymentViewModel(int intID)
        {
            DataCollection = _PaymentManager.GetPayments(intID);
        }

        #region INotifyPropertyChanged
        public event PropertyChangedEventHandler PropertyChanged;

        protected void RaisePropertyChanged(string propertyName)
        {
            if (PropertyChanged != null)
                PropertyChanged(this, new PropertyChangedEventArgs(propertyName));
        }
        #endregion

        private ObservableCollection<clsPayment> mDataCollection;

        public ObservableCollection<clsPayment> DataCollection
        {
            get { return mDataCollection; }
            set
            {
                mDataCollection = value;
                RaisePropertyChanged("DataCollection");
            }
        }

    }
/////////////////////////////////////////////////////////
    {
        public ObservableCollection<clsPayment> GetPayments(int intID)
        {
            ObservableCollection<clsPayment> ret;

            List<clsPayment> payments = GetPaymentsCol(intID);

            ret = new ObservableCollection<clsPayment>(payments);
            return ret;
        }

    }

clsPaymentViewModel _ViewModel;

public frmPayment()
        {
            InitializeComponent();

            int _intID = 1
            _ViewModel = new clsPaymentViewModel(_intID);
        }