Detecting events generated by a custom control

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Drawing;
using System.Data;
using System.Text;
using System.Windows.Forms;
 
namespace gridCustomControl
{
    public partial class GridCustomControl : UserControl
    {
        private int _cols = 3;
        private int _rows = 3;
        private int _width = 10;     // Cell width
        private int _height = 10;    // Cell height
        private float _zoom = 2f;
        private Color _cellColor = Color.White;
        private Color _borderColor = Color.Black;
        private const int WM_HSCROLL = 0x114;
        private const int WM_VSCROLL = 0x115;
 
        public GridCustomControl()
        {
            // We do not want to call InitializeComponent() from the
            // Designer of this custom control because we want the user
            // to be able to set the size of the control at design time.
            InitializeComponent();
 
            // The following SetStyles are needed for double buffering:
            this.SetStyle(ControlStyles.DoubleBuffer | 
                          ControlStyles.AllPaintingInWmPaint | 
                          ControlStyles.UserPaint, true);
 
            this.SetControlSize();
        }
 
        protected override void OnPaint(PaintEventArgs e)
        {
            Graphics g = e.Graphics;
            g.FillRectangle(Brushes.White, this.ClientRectangle);
 
            int cellHeight = this.CellHeight;
            int cellWidth = this.CellWidth;
            int nbrColumns = this.Columns;
            int nbrRows = this.Rows;
            int zoom = Convert.ToInt32(this.Zoom);
            Size scrollOffset;
 
            
 
            // Draw cells
            for (int row = 0; row < nbrRows; row++)
            {
                for (int col = 0; col < nbrColumns; col++)
                {
                    // Get negative x & y coordinates of scroll
                    scrollOffset = new Size(this.AutoScrollPosition);
 
                    // Calculate new cell location
                    // Detailed Explanation of example of offsets:
                    /* Assume the first cell top-left corner is located at x:0 y:0, 
                     * or (0,0). If there aren't any scrolling offsets, and the cell
                     * at (0,0) intersects with the ClipRectangle, then it will need
                     * to be painted. If there was scrolling of x:-100 (width) and
                     * y:-100 (height) then the cell at (-100, -100) will not be drawn
                     * because it is not within the 'viewport' and therefore there
                     * isn't a chance it intersects with the ClipRectangle. But if the
                     * original cell location was (100, 100) and the scrolling offset 
                     * size was (-100,-100) that would draw the cell at (0,0) of the 
                     * control. So the rule is that if the final location of the cell
                     * to be drawn is not negative, then it is within the viewport and
                     * MAY be redrawn if it intersects with the ClipRectangle.
                     */
                    
                    Point cellLocation = new Point(col * cellWidth + scrollOffset.Width, 
                                                   row * cellHeight + scrollOffset.Height);
 
                    // Define cell parameter
                    Rectangle cellRect = new Rectangle(cellLocation.X,
                                                       cellLocation.Y,
                                                       cellWidth, cellHeight);
 
                    // Only draw cell if it needs to be painted
                    if (cellRect.IntersectsWith(e.ClipRectangle))
                    {
                        g.FillRectangle(new SolidBrush(_cellColor), cellRect);
                        g.DrawRectangle(new Pen(_borderColor, 1), cellRect);
                    }
 
                    
                }
            }
        }
 
        public void SetControlSize()
        {
            // 1 is added otherwize the most very most right line and
            // the very most bottom line will not show.
            // this.Size = new Size(_width * _cols + 1, _height * _rows + 1);
 
            this.AutoScrollMinSize = new Size(this.CellWidth * 
                                     this.Columns , this.CellHeight * this.Rows );
            this.Invalidate(); // Redraw the whole control
        }
 
        [Browsable(true), 
         DesignerSerializationVisibility(DesignerSerializationVisibility.Visible),
         Description("The number of columns in the grid.")]
 
        public int Columns
        {
            get { return _cols; }
            set
            {
                _cols = value;
                this.SetControlSize();
            }
        }
 
        [Browsable(true),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Visible),
         Description("The number of rows in the grid.")]
        public int Rows
        {
            get { return _rows; }
            set
            {
                _rows = value;
                this.SetControlSize();
            }
        }
 
        [Browsable(true),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Visible),
         Description("The width, in pixels, of one cell.")]
        public int CellWidth
        {
            get { return _width; }
            set
            {
                _width = value;
                this.SetControlSize();
            }
        }
 
        [Browsable(false),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Visible), 
         Description("The height, in pixels, of one cell.")]
        public int CellHeight
        {
            get { return _height; }
            set
            {
                _height = value;
                this.SetControlSize();
            }
        }
 
        public float Zoom
        {
            get { return _zoom; }
            set
            {
                _zoom = value;
                this.SetControlSize();
            }
        }
 
        [Browsable(true),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Visible),
         Description("Height & width of this control")]
        public new Size Size
        {
            get { return base.Size; }
            set { base.Size = value; }
        }
 
        [Browsable(true),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Visible),
         Description("The color of the background inside of the cell.")]
        public Color CellColor
        {
            get { return _cellColor; }
            set
            {
                _cellColor = value;
                this.Invalidate();
            }
        }
 
        [Browsable(true),
        DesignerSerializationVisibility(DesignerSerializationVisibility.Visible),
         Description("The color of the border around the cell.")]
        public Color BorderColor
        {
            get { return _borderColor; }
            set
            {
                _borderColor = value;
                this.Invalidate();
            }
        }
 
        private void GridCustomControl_Scroll(object sender, ScrollEventArgs e)
        {
            //if (e.Type.ToString() != "ThumbTrack")
            //{
            //    Console.WriteLine(e.Type.ToString());
            //    Console.WriteLine(e.ScrollOrientation.ToString());
            //    Console.WriteLine(e.OldValue.ToString());
            //    Console.WriteLine(e.NewValue.ToString());
            //    Console.WriteLine("END");
            //    //this.Invalidate();
            //}
            //else
            //{
            //    Console.WriteLine(e.Type.ToString());
            //    Console.WriteLine(e.ScrollOrientation.ToString());
            //    Console.WriteLine(e.OldValue.ToString());
            //    Console.WriteLine(e.NewValue.ToString());
            //    Console.WriteLine("END");
            //    this.Invalidate();
            //}
        }
 
        
 
        protected override void WndProc(ref Message m)
        {
            if ((m.Msg == WM_HSCROLL || m.Msg == WM_VSCROLL)
                && (((int)m.WParam & 0xFFFF) == 5))
            {
                // Change SB_THUMBTRACK to SB_THUMBPOSITION
                m.WParam = (IntPtr)(((int)m.WParam & ~0xFFFF)
                           | 4);
            }
            base.WndProc(ref m);
        }
    }
}