ImageList img = new ImageList();
img.Images.Add(Image.FromFile("C:\\Program Files (x86)\\GrapeCity\\rasp.png"));
img.Images.Add(Image.FromFile("C:\\Program Files (x86)\\GrapeCity\\vanilla.png"));
img.Images.Add(Image.FromFile("C:\\Program Files (x86)\\GrapeCity\\choco.png"));
img.Images.Add(Image.FromFile("C:\\Program Files (x86)\\GrapeCity\\banana.png"));
GrapeCity.Win.Spread.InputMan.CellType.GcComboBoxCellType gccombo = new GrapeCity.Win.Spread.InputMan.CellType.GcComboBoxCellType();
gccombo.DropDownStyle = ComboBoxStyle.DropDownList;
gccombo.Items.AddRange(new String[] { "Raspberry", "Vanilla", "Chocolate", "Banana" });
gccombo.Items[0].BackColor = Color.Fuchsia;
gccombo.Items[1].BackColor = Color.Ivory;
gccombo.Items[2].BackColor = Color.Chocolate;
gccombo.Items[3].BackColor = Color.LightYellow;
gccombo.ImageList = img;
gccombo.Items[0].Image = 0;
gccombo.Items[1].Image = 1;
gccombo.Items[2].Image = 2;
gccombo.Items[3].Image = 3;
gccombo.ShowListBoxImage = true;
gccombo.ImageAlign = HorizontalAlignment.Right;
gccombo.ListSelectedItemStyle.BackColor = Color.Bisque;
gccombo.ListSelectedItemStyle.ForeColor = Color.Black;
gccombo.UnSelectedImageIndex = 1;
gccombo.TextBoxStyle = GrapeCity.Win.Spread.InputMan.CellType.TextBoxStyle.Both;
fpSpread1.Sheets[0].Cells[1, 1].CellType = gccombo;
fpSpread1.Sheets[0].Columns[1].Width = 200;
fpSpread1.Sheets[0].Rows[1].Height = 40;