public class SummaryCell : LabelCell 

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

namespace GrapeCity.Win.MultiRow.SampleCode
{
    public class SummaryCellDemo : Form
    {
        private GcMultiRow gcMultiRow1 = new GcMultiRow();

        private Label descriptionLable = new Label();

        public SummaryCellDemo()
        {
            this.Text = "SummaryCell Demo";
            this.Size = new Size(550, 300);

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

            descriptionLable.Height = 40;
            descriptionLable.BackColor = SystemColors.Info;
            descriptionLable.Dock = DockStyle.Bottom;
            descriptionLable.Text = "'Total', 'SubTotal' and 'Percentage' are SummaryCell. " +
                                    "SummaryCell can calculate cell value base on other cells' value. " +
                                    "Try to update price or add new record and watch what happened";
            this.Controls.Add(descriptionLable);

            this.Load += new EventHandler(Form1_Load);
        }

        private void Form1_Load(object sender, EventArgs e)
        {
            // create a template with SummaryCells.
            TextBoxCell nameTextBox = new TextBoxCell();

            NumericUpDownCell priceNumericUpDown = new NumericUpDownCell();
            priceNumericUpDown.ShowSpinButton = CellButtonVisibility.NotShown;
            priceNumericUpDown.DecimalPlaces = 2;
            priceNumericUpDown.Name = "Price";

            NumericUpDownCell countNumericUpDown = new NumericUpDownCell();
            countNumericUpDown.ShowSpinButton = CellButtonVisibility.NotShown;
            countNumericUpDown.Name = "Count";

            SummaryCell subTotalSummaryCell = CreateSubTotalSummaryCell();

            SummaryCell percentSummaryCell = CreateCustomSummaryCell();

            Cell[] cells = new Cell[] { nameTextBox, priceNumericUpDown, countNumericUpDown, subTotalSummaryCell, percentSummaryCell };

            Template template1 = Template.CreateGridTemplate(cells);

            ColumnFooterSection columnFooter = new ColumnFooterSection();
            columnFooter.Height = 21;
            template1.ColumnFooters.Add(columnFooter);

            SummaryCell totalSummaryCell = CreateTotalSummaryCell();
            totalSummaryCell.Location = subTotalSummaryCell.Location;
            columnFooter.Cells.Add(totalSummaryCell);

            LabelCell totalLabelCell = new LabelCell();
            totalLabelCell.Value = "Total:";
            totalLabelCell.Style.Border = Border.Empty;
            totalLabelCell.Location = countNumericUpDown.Location;
            columnFooter.Cells.Add(totalLabelCell);

            this.gcMultiRow1.Template = template1;
            this.gcMultiRow1.ColumnHeaders[0][0].Value = "Name";
            this.gcMultiRow1.ColumnHeaders[0][1].Value = "Price";
            this.gcMultiRow1.ColumnHeaders[0][2].Value = "Count";
            this.gcMultiRow1.ColumnHeaders[0][3].Value = "Sub Total";
            this.gcMultiRow1.ColumnHeaders[0][4].Value = "Percentage";

            this.FillValue();
        }
        private SummaryCell CreateSubTotalSummaryCell()
        {
            // Calculation the sub total base on 'Price' and 'Count' in same row.
            SummaryCell summaryCell = new SummaryCell();
            summaryCell.Name = "SubTotal";
            summaryCell.Calculation = new Expression("Price * Count");
            summaryCell.Style.Format = "C";
            summaryCell.Style.BackColor = Color.Wheat;
            return summaryCell;
        }
        private SummaryCell CreateTotalSummaryCell()
        {
            // Calculate sum of sub-total in all rows.
            SummaryCell summaryCell = new SummaryCell();
            summaryCell.Name = "Total";
            summaryCell.Calculation = new MathStatistics(StatisticsType.Sum, "SubTotal", true);
            summaryCell.Style.Format = "C";
            summaryCell.Style.BackColor = Color.Wheat;
            return summaryCell;
        }
        private SummaryCell CreateCustomSummaryCell()
        {
            SummaryCell summaryCell = new SummaryCell();
            // Custom calculation logic.
            summaryCell.Calculation = new PercentageCalculation();
            summaryCell.Style.Format = "#0.00%";
            summaryCell.Style.BackColor = Color.Wheat;
            return summaryCell;
        }

        class PercentageCalculation : ICalculation
        {
            public object Calculate(CalculationContext context)
            {
                // calculate the percentage base on current section's sub-total in total.
                object subTotalValue = context.GcMultiRow[context.SectionIndex, "SubTotal"].Value;
                object totalValue = context.GcMultiRow.ColumnFooters[0]["Total"].Value;

                if (object.Equals(totalValue, 0m))
                {
                    // context.ErrorInfo = "Total is 0.";
                    return "Total is 0";
                }

                return (decimal)subTotalValue / (decimal)totalValue;
            }

            public object Clone()
            {
                // If you and new property in the calculation, make sure the property is cloned in this method.
                return new PercentageCalculation();
            }
        }

        private void FillValue()
        {
            gcMultiRow1.Rows.Add("Apple", 2.25, 150);
            gcMultiRow1.Rows.Add("Banana", 8.3, 200);
            gcMultiRow1.Rows.Add("Watermelon", 5, 500);
            gcMultiRow1.Rows.Add("Pear", 3.2 , 355);
            gcMultiRow1.Rows.Add("Strawberry", 7.7, 440);
        }

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