I am testing the XamDataGrid and I am getting a Specified cast is not valid. when I try and sort a column by a value when the Value is Declared as Nullable, ie [?]

When I change the value to be not nullable I can then sort on that column, should you not be able to sort on Nullable POCO values? I tested with your xamdatacontrol control in Wpf, and that works just fine.

I get the following stack-trace back:

System.InvalidCastException: Specified cast is not valid.
07-07 09:50:51.131 I/MonoDroid( 6266):   at Infragistics.Controls.DataSource.Implementation.DataSourcePropertiesComparer.CompareValues (System.Object xValue, System.Object yValue, System.Boolean currIsDescending, Infragistics.Core.Controls.DataSource.DataSourceSchemaPropertyType schemaType) [0x00296] in E:\Work\1\1220\src\XPlatform\2017.1\Source\DataVisualization\Shared\DataSource\LocalDataSource.cs:780
07-07 09:50:51.131 I/MonoDroid( 6266):   at Infragistics.Controls.DataSource.Implementation.DataSourcePropertiesComparer.Compare (System.Object x, System.Object y) [0x00048] in E:\Work\1\1220\src\XPlatform\2017.1\Source\DataVisualization\Shared\DataSource\LocalDataSource.cs:629

In detail.

public class SelectEntity2
    {

        public int? ID { get; set; }


        public DateTime? NextDueDate { get; set; }
    }

 protected override void OnAppearing()
        {
            base.OnAppearing();
            if (DataGrid.ItemsSource == null)
            {
                CreateData();
                DataGrid.IsVisible = true;
            }
        }

        private void CreateData()
        {
            var items = new List<SelectEntity2>();

            for (int i = 1; i < 101; i++)
            {
                var days = new Random().Next(100);
                if (IsOdd(days))
                  items.Add(new SelectEntity2 {ID = i, NextDueDate = DateTime.Now.AddDays(days)});
                else
                {
                    items.Add(new SelectEntity2 { ID = i, NextDueDate = DateTime.Now.AddDays(-days) });
                }
            }
            DataGrid.AutoGenerateColumns = true;            
            DataGrid.ItemsSource = items;
            
        }

        public static bool IsOdd(int value)
        {
            return value % 2 != 0;
        }