I created ValueToDisplayTextConverter for show in a one cell of a XamDataGrid both string and numeric data . The format property is using to change accuracy.

public class ValueToDisplayTextConverter : IValueConverter

    {

        public static string Format = "{0:0.00}";

        public object Convert(object value, Type targetType, object parameter,  System.Globalization.CultureInfo culture){.....}

      ..........

    }

When i need to change accuracy then i set another value to the format property and reload DataSource of a XamDataGrid:

        protected double scrollOffset = 0;

        public void UpdateAccuracy(string newFormat )

        {

            ValueToDisplayTextConverter .Format = newFormat;

            scrollOffset = DGridDelivery.ScrollInfo.VerticalOffset;

            DGridDelivery.DataSource = null;

            DGridDelivery.DataSource = dataSource.DefaultView;

        }

        void DGridDelivery_LayoutUpdated(object sender, EventArgs e)

        {

            DGridDelivery.LayoutUpdated -= new EventHandler(DGridDelivery_LayoutUpdated);

            DGridDelivery.ScrollInfo.SetVerticalOffset(scrollOffset);

        }

But some cell with similar values (like an "1,111" and "1,111")  into them do not call converter and do not change display value. 

I spent much time but can't to solve this problem.