How to group a column with DateTime values without showing its time part in SfDataGrid?

<sfgrid:GridTextColumn MappingName="ShippingDate" Format="dd/MM/yyyy" />

<sfgrid:SfDataGrid.GroupColumnDescriptions>

<sfgrid:GroupColumnDescription ColumnName="ShippingDate" Converter="{StaticResource groupDateTimeConverter}" />
</sfgrid:SfDataGrid.GroupColumnDescriptions>

public class CustomSortComparer : IComparer<object>, ISortDirection

{

    #region Property

    public ListSortDirection SortDirection { get; set; }

    #endregion

    #region Constructor

    public CustomSortComparer()

    {

    }

    #endregion

    #region Compare

    public int Compare(object x, object y)

    {

        DateTime dateX = DateTime.MaxValue;

        DateTime dateY = DateTime.MaxValue;

        if (x.GetType() == typeof(OrderInfo))

        {

            dateX = ((OrderInfo)x).ShippingDate;

            dateY = ((OrderInfo)y).ShippingDate;

        }

        else if (x.GetType() == typeof(Group))

        {

            dateX = DateTime.ParseExact(((Group)x).Key.ToString(),

                                                                 "dd/MM/yyyy", CultureInfo.InvariantCulture);

            dateY = DateTime.ParseExact(((Group)y).Key.ToString(),

                                                                "dd/MM/yyyy", CultureInfo.InvariantCulture);

        }

        else

        {

            dateX = (DateTime)x;

            dateY = (DateTime)y;

        }

        if (DateTime.Compare(dateX, dateY) >= 0)

            return SortDirection == ListSortDirection.Ascending ? 1 : -1;

        else

            return SortDirection == ListSortDirection.Ascending ? -1 : 1;

    }

    #endregion

}