GrapeCity.Win.Spread.InputMan.CellType.GcComboBoxCellType gccombo = new GrapeCity.Win.Spread.InputMan.CellType.GcComboBoxCellType();
gccombo.DropDownStyle = ComboBoxStyle.DropDownList;
gccombo.ListGradientEffect = new GrapeCity.Win.Spread.InputMan.CellType.GradientEffect(GrapeCity.Win.Spread.InputMan.CellType.GradientStyle.Circular, GrapeCity.Win.Spread.InputMan.CellType.GradientDirection.Backward, Color.Blue, Color.Yellow);
gccombo.Items.AddRange(new string[] { "Feta", "Havarti", "Swiss" });
fpSpread1.Sheets[0].Cells[1, 1].CellType = gccombo;