GetRawData() returns an instance of the IListToChartAdapter2 attached to your list.

GetStringValue(row, column) returns this

return this.internalNTV[row][column].Value.ToString();

where "internalNTV" is an array of objects containing Name, Type, and Value information on your objects.  this is all retrieved using TypeDescriptor.GetProperties and PropertyDescriptor.GetValue.

maybe if any of your properties have a value of null then some problem is occurring.  but if this is only occurring on some machines, you might want to try installing the latest .NET Framework service pack.

if you have a sample project or steps to reproduce, i could also help look into this.

here's my sample which should solve the problem with ICustomTypeDescriptor and a BindingList.

to answer your other question, the chart's API is the way it is because it was designed with only DataTables in mind, then expanded to support other datasources as well.  not ideal in this particular situation, but the workaround has always done the job for us.

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            this.ultraChart1.ChartType = ChartType.ScatterChart;
            this.ultraChart1.ScatterChart.ColumnX = 0;
            this.ultraChart1.ScatterChart.ColumnY = 1;
            this.ultraChart1.Data.DataSource = new BindingList<Widget>(new Widget[]
            {
                new Widget(1, 3),
                new Widget(2, 2),
                new Widget(3, 1),
            });
           
        }
        public class Widget : ICustomTypeDescriptor
        {
            public Widget(double x, double y)
            {
                this.TheXValue = x;
                this.TheYValue = y;
            }

            public double TheXValue { get; set; }
            public double TheYValue { get; set; }
            public double IrrelevantProperty { get; set; }

           
            #region ICustomTypeDescriptor Members

            AttributeCollection ICustomTypeDescriptor.GetAttributes()
            {
                return null;
            }

            string ICustomTypeDescriptor.GetClassName()
            {
                return null;
            }

            string ICustomTypeDescriptor.GetComponentName()
            {
                return null;
            }

            TypeConverter ICustomTypeDescriptor.GetConverter()
            {
                return null;
            }

            EventDescriptor ICustomTypeDescriptor.GetDefaultEvent()
            {
                return null;
            }

            PropertyDescriptor ICustomTypeDescriptor.GetDefaultProperty()
            {
                return null;
            }

            object ICustomTypeDescriptor.GetEditor(Type editorBaseType)
            {
                return null;
            }

            EventDescriptorCollection ICustomTypeDescriptor.GetEvents(Attribute[] attributes)
            {
                return null;
            }

            EventDescriptorCollection ICustomTypeDescriptor.GetEvents()
            {
                return null;
            }

            PropertyDescriptorCollection ICustomTypeDescriptor.GetProperties(Attribute[] attributes)
            {
                return null;
            }

            PropertyDescriptorCollection ICustomTypeDescriptor.GetProperties()
            {
                PropertyDescriptorCollection originalProps = TypeDescriptor.GetProperties(this, true); // passing true as the 2nd argument here will ignore the ICustomTypeDescriptor implementation
                return new PropertyDescriptorCollection(new PropertyDescriptor[]
                {
                    originalProps["TheXValue"],
                    originalProps["TheYValue"]
                });
            }
            object ICustomTypeDescriptor.GetPropertyOwner(PropertyDescriptor pd)
            {
                return this;
            }

            #endregion
        }
    }