Populating a DataGridView with Text and ProgressBars

I added class DataGridViewProgressColumn.cs (source: MSDN)

using System;
using System.Collections.Generic;
using System.Text;
using System.Windows.Forms;
using System.Drawing;
using System.ComponentModel;
namespace Sample
{
    public class DataGridViewProgressColumn : DataGridViewImageColumn
    {
        public DataGridViewProgressColumn()
        {
            CellTemplate = new DataGridViewProgressCell();
        }
    }
}
namespace Sample
{
    class DataGridViewProgressCell : DataGridViewImageCell
    {
        // Used to make custom cell consistent with a DataGridViewImageCell
        static Image emptyImage;
        static DataGridViewProgressCell()
        {
            emptyImage = new Bitmap(1, 1, System.Drawing.Imaging.PixelFormat.Format32bppArgb);
        }
        public DataGridViewProgressCell()
        {
            this.ValueType = typeof(int);
        }
        // Method required to make the Progress Cell consistent with the default Image Cell. 
        // The default Image Cell assumes an Image as a value, although the value of the Progress Cell is an int.
        protected override object GetFormattedValue(object value,
                            int rowIndex, ref DataGridViewCellStyle cellStyle,
                            TypeConverter valueTypeConverter,
                            TypeConverter formattedValueTypeConverter,
                            DataGridViewDataErrorContexts context)
        {
            return emptyImage;
        }
    protected override void Paint(System.Drawing.Graphics g, System.Drawing.Rectangle clipBounds, System.Drawing.Rectangle cellBounds, int rowIndex, DataGridViewElementStates cellState, object value, object formattedValue, string errorText, DataGridViewCellStyle cellStyle, DataGridViewAdvancedBorderStyle advancedBorderStyle, DataGr