FarPoint.Win.Spread.CellType.ComboBoxCellType cmbocell = new FarPoint.Win.Spread.CellType.ComboBoxCellType();
ListBox list = new ListBox();
list.Items.AddRange(new Object[] {"One", "Two", "Three"});
cmbocell.ListControl = list;
cmbocell.Items = (new String[] {"", "", ""});
fpSpread1.ActiveSheet.Columns[0].CellType = cmbocell;