// master has 4 columns (include hierarchicalColumn) and details have 1 column.
for (int i = 0; i < 5; i++)
{
    flyGrid1.Rows.Items.Add(new Node(new object[] { null, null, null, i }));
    flyGrid1.Rows.Items[flyGrid1.Rows.Items.Count - 1].Items.Add(new Node(new object[] { i + 100 }));
}

[c#]
NestedGridNode masterNode = new NestedGridNode(new object[] { null, null, 5, \"Some Data\" });
//add nested nodes
for(int i = 0; i < 5; i++)
{
  NodeBase child = new Node(new object[] { null, null, \"Some Child Data\", i });
  masterNode.Add(child);
}

        public Form2()
        {
            InitializeComponent();

            this.numberColumn2 = new NineRays.Windows.Forms.Grids.NumberColumn();
            this.numberColumn2.Caption = \"Child\";
            this.numberColumn2.ImageKey = null;
            this.numberColumn2.NumberType = System.TypeCode.Int32;

            flyGrid1.Columns.NestedColumns.Items.Add(numberColumn2);

            Node master = new Node(new object[] { null, 99 });

            NestedGridNode[] children = new NestedGridNode[5];
            //add nested nodes
            for (int i = 0; i < 5; i++)
            {
                children[i] = new NestedGridNode();
                children[i].Value = new Node(new object[] { i });
            }
            master.Items.AddRange(children);

            flyGrid1.Rows.Items.Add(master);
        }

children[i].Value = new object[] { i };