GridControl UnboundColumn使用其它表列

namespace dxExample
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
            // Create data
            ds = new DataSet();
            ds.Tables.Add(GetOrderData());
            ds.Tables.Add(GetCustomerData());
            gridControl1.DataSource = ds.Tables[0];
            // Hide the customerID column
            gridView1.Columns["customerID"].Visible = false;
            // Add an unbound column
            GridColumn col = gridView1.Columns.AddField("custID");
            col.Visible = true;
            col.UnboundType = DevExpress.Data.UnboundColumnType.String;
            col.OptionsColumn.AllowEdit = false;
            // event for populating this column with data
            gridView1.CustomUnboundColumnData += new DevExpress.XtraGrid.Views.Base.CustomColumnDataEventHandler(gridView1_CustomUnboundColumnData);
        }
        DataSet ds;
        void gridView1_CustomUnboundColumnData(object sender, DevExpress.XtraGrid.Views.Base.CustomColumnDataEventArgs e)
        {
            if (e.Column.FieldName == "custID")
            {
                if (e.IsGetData)
                {
                    object custID = gridView1.GetRowCellValue(e.ListSourceRowIndex, "customerID"); // Get customer ID from the Orders table
                    e.Value = ds.Tables["Customers"].Rows.Find(custID)["customerName"]; // set the required value
                }
            }
        }

        DataTable GetOrderData()
        {
            DataTable dt = new DataTable();
            dt.TableName = "Orders";
            dt.Columns.Add("orderID", typeof(int));
            dt.Columns.Add("orderName", typeof(string));
            dt.Columns.Add("customerID", typeof(int));
            dt.Rows.Add(1, "Order1", 1);
            dt.Rows.Add(2, "Order2", 1);
            dt.Rows.Add(3, "Order3", 2);
            dt.Rows.Add(4, "Order4", 2);
            dt.Rows.Add(5, "Order5", 1);
            return dt;
        }

        DataTable GetCustomerData()
        {
            DataTable dt = new DataTable();
            dt.TableName = "Customers";
            dt.Columns.Add("customerID", typeof(int));
            dt.Columns.Add("customerName", typeof(string));
            dt.Rows.Add(1, "Alfred");
            dt.Rows.Add(2, "Matt");
            DataColumn[] keys = new DataColumn[1];
            keys[0] = dt.Columns[0];
            dt.PrimaryKey = keys;
            return dt;
        }        
    }
}