public class GcComboBoxCell : InputManCellBase 

using System;
using System.Windows.Forms;
using System.Drawing;

namespace GrapeCity.Win.MultiRow.InputMan.SampleCode
{
    class GcComboBoxCellDemo : Form
    {
        private GcMultiRow gcMultiRow1 = new GcMultiRow();
        private Label label = new Label();

        public GcComboBoxCellDemo()
        {
            this.Text = "GcComboBoxCell Demo";
            this.Size = new Size(350, 300);

            // Add MultiRow to form
            this.gcMultiRow1.Dock = DockStyle.Fill;
            this.Controls.Add(this.gcMultiRow1);

            this.label.Dock = DockStyle.Bottom;
            this.label.Height = 50;
            this.label.BackColor = SystemColors.Info;
            this.label.Text = " You can select one item from the DropDownList; In edit mode, hit the F6 to clear the content.";
            this.Controls.Add(label);

            this.Load += new EventHandler(Form1_Load);

            this.StartPosition = FormStartPosition.CenterScreen;
        }
        private void Form1_Load(object sender, EventArgs e)
        {
            GcComboBoxCell gcComboBoxCell1 = new GcComboBoxCell();
            gcComboBoxCell1.DropDownStyle = MultiRowComboBoxStyle.DropDown;

            gcComboBoxCell1.Items.AddRange(new string[] { "One", "Two", "Three" });

            //In edit mode, hit the F6 to clear the content.
            gcComboBoxCell1.ShortcutKeys.Add(Keys.F6, "ShortcutClear");

            Template template1 = Template.CreateGridTemplate(new Cell[] { gcComboBoxCell1, gcComboBoxCell1.Clone() as Cell }, 160,
                AutoGenerateGridTemplateStyles.ColumnHeader | AutoGenerateGridTemplateStyles.RowHeaderAutoNumber);

            gcMultiRow1.Template = template1;
            gcMultiRow1.RowCount = 3;
        }

        [STAThreadAttribute()]
        public static void Main()
        {
            Application.EnableVisualStyles();
            Application.Run(new GcComboBoxCellDemo());
        }
    }
}