FarPoint.Win.Spread.CellType.ComboBoxCellType cmbocell = new FarPoint.Win.Spread.CellType.ComboBoxCellType();
cmbocell.Items = (new String[] {"One", "Two", "Three", "Four", "Five"});
cmbocell.BackgroundImage = new FarPoint.Win.Picture(Image.FromFile("..\\images\\skybg.gif"));
cmbocell.Editable = false;
fpSpread1.ActiveSheet.Columns[0, 2].CellType = cmbocell;