AutoCompleteStringCollection acsc = new AutoCompleteStringCollection();
acsc.AddRange(new string[] { "Gouda", "Swiss", "Brie" });
GrapeCity.Win.Spread.InputMan.CellType.GcComboBoxCellType gccombo = new GrapeCity.Win.Spread.InputMan.CellType.GcComboBoxCellType();
gccombo.Items.Add("Gouda");
gccombo.Items.Add("Swiss");
gccombo.Items.Add("Brie");
gccombo.AutoCompleteCustomSource = acsc;
gccombo.AutoCompleteMode = AutoCompleteMode.Suggest;
gccombo.AutoCompleteSource = AutoCompleteSource.CustomSource;
fpSpread1.Sheets[0].Cells[0, 0].CellType = gccombo;