Rendering a generated table with TableLayoutPanel taking too long to finish

Question

My program is pretty straight forward in concept - it allows a user to take scores during bowling tournaments, as well as showing the players the scores through a scoreboard.

There's a score sheet form in which they enter scores, and a scoreboard form that shows the scores to the players, by division. The scoreboard is run in a different thread than the main program.

The scoreboard is comprised of a TableLayoutPanel which I manipulate programmatically to represent a table of the scores to show. My issue with this is that it takes a long time (especially for a long list of players) for the table to render. The user experience of watching the table render itself leaves to be desired as well.

I tested the speed of rendering textboxes, labels, and picture boxes to lessen the load; textboxes won, so I changed the score labels to textboxes... but it's still not enough.

It's a lot to look through, but if anyone has any idea how I could further speed up the rendering of the scoreboard, I'd be all ears/eyes.

Here's my process broken down.

The calling method (called every 15 seconds by a timer):

    private void switchBoard()
    {
        night = nights.GetNight(nightID);
        NightDay = night.Night_Date.ToString("ddd");
        //set the id of the division to show
        dtDivisions = scoreBoard.roll_display(dtDivisions);
        //get the row that is set to show
        DataRow[] drs = dtDivisions.Select("showing = 1");
        DataRow dr = drs[0];
        //update the title
        lbl_title.Top = 30;
        lbl_title.Text = (string)dr["title"] + "'s Qualifying - " + NightDay;
        lbl_title.Width = this.Width;
        lbl_title.TextAlign = ContentAlignment.MiddleCenter;
        //SET UP THE TABLE
        //get number of columns (games) for selected night
        int Cols = games.GetCountGamesForTourNightByDivision(tourID, nightID, scoreBoard.ShowDivision) + 3; //ACCOUNT FOR HEADER COLS, RANK AND TOTALS
        //get number of rows (players) for selected night
        int Rows = players.GetCountPlayersForTourNightByDivision(TourID, nightID, scoreBoard.ShowDivision) + 1; //ACCOUNT FOR HEADER ROWS
        //generate the table
        GenerateTable(Cols, Rows);
        //generate the headers
        GenerateHeaders(tourID, nightID);
        //fill in the scores
        GenerateScoreLabels(tourID, nightID, scoreBoard.ShowDivision);
    }

Generating the table:

    private void GenerateTable(int columnCount, int rowCount)
    {
        //Clear out the existing controls, we are generating a new table layout
        this.tblPnlScoreboard.Controls.Clear();

        //Clear out the existing row and column styles
        this.tblPnlScoreboard.ColumnStyles.Clear();
        this.tblPnlScoreboard.RowStyles.Clear();

        //setting up the row and column counts
        this.tblPnlScoreboard.ColumnCount = columnCount;
        this.tblPnlScoreboard.RowCount = rowCount;

        for (int x = 0; x < columnCount; x++)
        {
            //add a column
            if(x==0) //ranking column
            {
                this.tblPnlScoreboard.ColumnStyles.Add(new ColumnStyle(SizeType.Absolute,30));
            }
            else if(x==1) //names
            {
                this.tblPnlScoreboard.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
            }
            else if(x==columnCount-1) //totals
            {
                this.tblPnlScoreboard.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
            }
            else //games
            {
                this.tblPnlScoreboard.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, (this.tblPnlScoreboard.Width - 130) / columnCount));
            }

            for (int y = 0; y < rowCount; y++)
            {
                //add rows.  Only do this once, when creating the first column
                if (x == 0)
                {
                    if(y==0)
                    {
                        this.tblPnlScoreboard.RowStyles.Add(new RowStyle(SizeType.Absolute, 50));
                    }
                    else
                    {
                        this.tblPnlScoreboard.RowStyles.Add(new RowStyle(SizeType.AutoSize));
                    }

                }
            }
        }
    }

Generating the headers:

    private void GenerateHeaders(int TourID, int NightID)
    {
        //get the players to display
        DataTable dtPlayers = players.GetPlayersForTourNightByDivision(tourID, nightID, scoreBoard.ShowDivision);

        int Row = 1; //0 is the header row for Games and so on
        foreach (DataRow dr in dtPlayers.Rows)
        {
            //create the label
            Label lblPlayer = new Label();
            lblPlayer.Name = dr["ID"].ToString(); //name is the ID of the player
            lblPlayer.Text = dr["player_name"].ToString(); //the text is the name of the player
            lblPlayer.BackColor = Color.Transparent;
            lblPlayer.Font = new Font("Microsoft Sans Serif", 25, FontStyle.Bold);
            lblPlayer.TextAlign = ContentAlignment.MiddleLeft;
            lblPlayer.AutoSize = true;
            lblPlayer.Height = tblPnlScoreboard.GetRowHeights()[Row];
            //add the label to the table
            this.tblPnlScoreboard.Controls.Add(lblPlayer, 1, Row);

            //create the Total label
            Label lblTotal = new Label();
            lblTotal.Name = "lbl_total"; //name is arbitrary in this context
            lblTotal.Text = dr["Total"].ToString(); //the text is the total
            lblTotal.BackColor = Color.Transparent;
            lblTotal.Font = new Font("Microsoft Sans Serif", 25, FontStyle.Bold);
            lblTotal.TextAlign = ContentAlignment.MiddleLeft;
            lblTotal.AutoSize = true;
            lblTotal.Height = tblPnlScoreboard.GetRowHeights()[Row];
            //add the label to the table
            this.tblPnlScoreboard.Controls.Add(lblTotal, tblPnlScoreboard.ColumnCount, Row);

            //increment the row index
            Row++;
        }

        //totals column
        Label lblTotals = new Label();
        //lblTotals.Width = this.tblPnlScoreboard.GetColumnWidths()[this.tblPnlScoreboard.ColumnCount - 1];
        lblTotals.Height = tblPnlScoreboard.GetRowHeights()[0];
        lblTotals.Name = "lbl_total"; //name is the ID of the Game
        lblTotals.Text = "Totals"; //text is the display name of the Game
        lblTotals.BackColor = Color.Transparent;
        lblTotals.ForeColor = Color.White;
        lblTotals.Font = new Font("Microsoft Sans Serif", 25, FontStyle.Bold);
        lblTotals.TextAlign = ContentAlignment.MiddleCenter;
        lblTotals.AutoSize = true;
        lblTotals.Anchor = (AnchorStyles.None);
        //add the label to the table
        this.tblPnlScoreboard.Controls.Add(lblTotals, this.tblPnlScoreboard.ColumnCount-1, 0);

        //get the games to display
        DataTable dtGames = games.GetGamesForTourNightByDivision(tourID, nightID, scoreBoard.ShowDivision);

        int Col = 2; //0 is the header column for rank, 1 is the header col for Players
        foreach (DataRow dr in dtGames.Rows)
        {
            //create the label
            Label lblGame = new Label();
            lblGame.Width = this.tblPnlScoreboard.GetColumnWidths()[Col];
            lblGame.Height = tblPnlScoreboard.GetRowHeights()[0];
            lblGame.Name = dr["ID"].ToString(); //name is the ID of the Game
            lblGame.Text = dr["disp_name"].ToString().Replace("Game ", ""); //text is the display name of the Game
            lblGame.BackColor = Color.Transparent;
            lblGame.ForeColor = Color.White;
            lblGame.Font = new Font("Microsoft Sans Serif", 25, FontStyle.Bold);
            lblGame.TextAlign = ContentAlignment.MiddleCenter;
            lblGame.Anchor = (AnchorStyles.None);
            //add the label to the table
            this.tblPnlScoreboard.Controls.Add(lblGame, Col, 0);
            //increment the column index
            Col++;
        }
    }

Finally, generating the scores:

    private void GenerateScoreLabels(int TourID, int NightID, int DivID)
    {
        //get the id of the playergames record
        //expl: each player/game pair has a unique ID - these IDs will be used to update the scores
        Players players = new Players();
        DataTable dtScores = players.GetPlayerGamesIDsForTourNightByDivision(TourID, NightID, scoreBoard.ShowDivision);
        Divisions Divs = new Divisions();
        DataTable dtColors = Divs.GetDivisionScoreboardColors(DivID);

        foreach (DataRow dr in dtScores.Rows)
        {
            //find the coordinates in the table, where the textbox should be added
            int col = FindX((int)dr["fk_game_id"]);
            int row = FindY((int)dr["fk_player_id"]);

            if (col > 0 && row > 0)
            {                   
                TextBox txt_score = new TextBox();
                txt_score.Name = dr["ID"].ToString(); //name of the control is the player/game ID
                txt_score.Text = dr["score"].ToString(); //the text in the control is the score
                txt_score.ForeColor = Color.Black;
                txt_score.Font = new Font("Microsoft Sans Serif", 25, FontStyle.Bold);
                txt_score.Width = this.tblPnlScoreboard.GetColumnWidths()[col];
                txt_score.Height = tblPnlScoreboard.GetRowHeights()[0];
                if(row % 2 == 0)
                {
                    txt_score.BackColor = Color.FromArgb((int)dtColors.Rows[0]["sb_even_row_color"]);
                }
                else
                {
                    txt_score.BackColor = Color.FromArgb((int)dtColors.Rows[0]["sb_odd_row_color"]);
                }
                txt_score.BorderStyle = BorderStyle.None;
                txt_score.TextAlign = HorizontalAlignment.Center;
                txt_score.Anchor = (AnchorStyles.Top);

                this.tblPnlScoreboard.Controls.Add(txt_score, col, row);

                //start the switchboard timer
                ttmr_switch.Enabled = true;
            }
        }
    }

On the CellPaint event of the TableLayoutPanel, I have these processes:

    private void tblPnlScoreboard_CellPaint(object sender, TableLayoutCellPaintEventArgs e)
    {
        Graphics g = e.Graphics;
        Rectangle r = e.CellBounds;
        SolidBrush sb = GetBrushFor(e.Row, e.Column, scoreBoard.ShowDivision);

        g.FillRectangle(sb, r);
        sb.Dispose();
    }

Selection of Colors:

    private SolidBrush GetBrushFor(int row, int column, int DivID)
    {
        DataTable dt_colors = divisions.GetDivisionScoreboardColors(DivID);

        if (row == 0)
        {   //column headers
            SolidBrush brush = new SolidBrush(Color.FromArgb((int)dt_colors.Rows[0]["sb_column_header_color"]));
            return brush;
        }
        else
        {   
            if(row % 2 == 0) //even row
            {
                SolidBrush brush = new SolidBrush(Color.FromArgb((int)dt_colors.Rows[0]["sb_even_row_color"]));
                return brush;
            }
            else //odd row
            {
                SolidBrush brush = new SolidBrush(Color.FromArgb((int)dt_colors.Rows[0]["sb_odd_row_color"]));
                return brush;
            }
        }
    }

Answer 1

Some people suggested you to use a "proper technology". I would rather say "use properly the technology". Even this weird (sorry) design/implementation choice can be made to work much faster, as shown in the code below, which as you may see is handling rebuilding a table containing 100 rows x 10 columns 10 times per sec - not a big deal compared to professional grids, but far from the original implementation. Key points:
1. Enclose table rebuild with Suspend/ResumeLayout to avoid intensive recalculations during the process.
2. Use custom double buffered TableLayoutPanel to avoid flickering.
3. Custom paint the data cells to avoid allocating a lot of controls.

Since essential data related parts are missing in the code you gave us, I can't provide you exactly the same working code. Hope you can recognize and map it to your stuff.

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace Tests
{
    static class Program
    {
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new ScoreBoardForm { WindowState = FormWindowState.Maximized });
        }
    }

    class ScoreBoardForm : Form
    {
        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);

            players = new List<Player>();
            for (int i = 0; i < 100; i++)
                players.Add(new Player { ID = i + 1, Name = "P" + (i + 1), Total = random.Next(1000) });
            games = new List<Game>();
            for (int i = 0; i < 10; i++)
                games.Add(new Game { ID = i + 1, Name = "G" + (i + 1) });

            scoreBoardTable = new ScoreBoardTable { Dock = DockStyle.Fill, Parent = this };
            scoreBoardTable.Bounds = this.DisplayRectangle;
            UpdateScoreBoard();
            scoreBoardTable.CellPaint += OnScoreBoardTableCellPaint;

            updateTimer = new Timer { Interval = 100 };
            updateTimer.Tick += (_sender, _e) => UpdateScoreBoard();
            updateTimer.Start();
        }
        private void OnScoreBoardTableCellPaint(object sender, TableLayoutCellPaintEventArgs e)
        {
            int playerIndex = e.Row - 1, gameIndex = e.Column - 2;
            if (playerIndex >= 0 && playerIndex < players.Count && gameIndex >= 0 && gameIndex < games.Count)
            {
                using (var br = new SolidBrush(GetBackColor(e.Row)))
                    e.Graphics.FillRectangle(br, e.CellBounds);
                var score = GetScore(players[playerIndex], games[gameIndex]);
                var sf = new StringFormat { Alignment = StringAlignment.Far, LineAlignment = StringAlignment.Center };
                e.Graphics.DrawString(score.ToString(), defaultCellFont, Brushes.Black, e.CellBounds, sf);
            }
        }
        private int GetScore(Player player, Game game)
        {
            return random.Next(10000);
        }
        class ScoreBoardTable : TableLayoutPanel
        {
            public ScoreBoardTable() { DoubleBuffered = AutoScroll = true; }
        }
        TableLayoutPanel scoreBoardTable;
        Timer updateTimer;
        List<Player> players;
        List<Game> games;
        Random random = new Random();
        class Player
        {
            public int ID;
            public string Name;
            public int Total;
        }
        class Game
        {
            public int ID;
            public string Name;
        }
        private void UpdateScoreBoard()
        {
            scoreBoardTable.SuspendLayout();
            GenerateTable(games.Count + 3, players.Count + 1);
            GenerateHeaderCells();
            // Custom cell paint is much faster, but requires a good data model.
            // If you uncomment the following line, make sure to get rid of CellPaint. 
            //GenerateScoreCells();
            scoreBoardTable.ResumeLayout(true);
        }
        private void GenerateTable(int columnCount, int rowCount)
        {
            scoreBoardTable.Controls.Clear();
            scoreBoardTable.ColumnStyles.Clear();
            scoreBoardTable.RowStyles.Clear();
            scoreBoardTable.ColumnCount = columnCount;
            scoreBoardTable.RowCount = rowCount;

            // Columns
            // Ranking
            scoreBoardTable.ColumnStyles.Add(new ColumnStyle(SizeType.Absolute, 30));
            // Name 
            scoreBoardTable.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));
            // Games
            var percent = (columnCount - 3) / (float)columnCount;
            for (int col = 2; col < columnCount - 1; col++)
                scoreBoardTable.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, percent));
            // Totals
            scoreBoardTable.ColumnStyles.Add(new ColumnStyle(SizeType.AutoSize));

            // Rows
            // Header
            scoreBoardTable.RowStyles.Add(new RowStyle(SizeType.Absolute, 50));
            // Players
            for (int row = 1; row < rowCount; row++)
                scoreBoardTable.RowStyles.Add(new RowStyle(SizeType.AutoSize));
        }
        private void GenerateHeaderCells()
        {
            Color backColor = Color.DarkGray, foreColor;
            int row, col;
            // Header
            row = 0;
            foreColor = Color.White;
            col = 0;
            AddCell(row, col++, "rank", "", foreColor, backColor);
            AddCell(row, col++, "playerName", "Player", foreColor, backColor);
            foreach (var game in games)
                AddCell(row, col++, "gameName" + game.ID, game.Name, foreColor, backColor);
            AddCell(row, col, "totalColumn", "Totals", foreColor, backColor);
            // Rows
            foreColor = Color.Black;
            row++;
            foreach (var player in players)
            {
                backColor = GetBackColor(row);
                AddCell(row, 0, "playerRank_" + player.ID, "", foreColor, backColor, ContentAlignment.MiddleLeft);
                AddCell(row, 1, "playerName_" + player.ID, player.Name, foreColor, backColor, ContentAlignment.MiddleLeft);
                AddCell(row, scoreBoardTable.ColumnCount, "playerTotal_" + player.ID, player.Total.ToString(), foreColor, backColor, ContentAlignment.MiddleRight);
                row++;
            }
        }
        private void GenerateScoreCells()
        {
            var foreColor = Color.Black;
            int row = 1;
            foreach (var player in players)
            {
                var backColor = GetBackColor(row);
                int col = 2;
                foreach (var game in games)
                {
                    var score = GetScore(player, game);
                    AddCell(row, col, "score_" + player.ID + "_" + game.ID, score.ToString(), foreColor, backColor, ContentAlignment.MiddleRight, false);
                    col++;
                }
                row++;
            }
        }
        static readonly Font defaultCellFont = new Font("Microsoft Sans Serif", 25, FontStyle.Bold);
        private Label AddCell(int row, int col, string name, string text, Color foreColor, Color backColor, ContentAlignment textAlign = ContentAlignment.MiddleCenter, bool autoSize = true)
        {
            var label = new Label();
            label.Name = name;
            label.Text = text;
            label.BackColor = backColor;
            label.ForeColor = foreColor;
            label.Font = defaultCellFont;
            label.TextAlign = textAlign;
            label.AutoSize = autoSize;
            label.Margin = new Padding(0);
            label.Dock = DockStyle.Fill;
            scoreBoardTable.Controls.Add(label, col, row);
            return label;
        }
        static Color GetBackColor(int row)
        {
            if (row % 2 == 0) //even row
                return Color.Yellow;
            else //odd row
                return Color.LightGreen;
        }
    }
}

EDIT And here is equivalent implementation using DataGridView (note that now the number of rows (players) are ten times more at the same refresh rate):

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace Tests
{
    static class Program
    {
        [STAThread]
        static void Main()
        {
            Application.EnableVisualStyles();
            Application.SetCompatibleTextRenderingDefault(false);
            Application.Run(new ScoreBoardForm { WindowState = FormWindowState.Maximized });
        }
    }

    class ScoreBoardForm : Form
    {
        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);

            players = new List<Player>();
            for (int i = 0; i < 1000; i++)
                players.Add(new Player { ID = i + 1, Name = "P" + (i + 1), Total = random.Next(1000) });
            games = new List<Game>();
            for (int i = 0; i < 10; i++)
                games.Add(new Game { ID = i + 1, Name = "G" + (i + 1) });

            InitScoreBoard();
            UpdateScoreBoard();

            updateTimer = new Timer { Interval = 100 };
            updateTimer.Tick += (_sender, _e) => UpdateScoreBoard();
            updateTimer.Start();
        }

        DataGridView scoreBoardTable;
        Timer updateTimer;
        List<Player> players;
        List<Game> games;
        Random random = new Random();
        class Player
        {
            public int ID;
            public string Name;
            public int Total;
        }
        class Game
        {
            public int ID;
            public string Name;
        }
        private int GetScore(Player player, Game game)
        {
            return random.Next(10000);
        }
        void InitScoreBoard()
        {
            scoreBoardTable = new DataGridView { Dock = DockStyle.Fill, Parent = this };
            scoreBoardTable.Font = new Font("Microsoft Sans Serif", 25, FontStyle.Bold);
            scoreBoardTable.SelectionMode = DataGridViewSelectionMode.FullRowSelect;
            scoreBoardTable.MultiSelect = false;
            scoreBoardTable.CellBorderStyle = DataGridViewCellBorderStyle.None;
            scoreBoardTable.BackgroundColor = Color.Honeydew;
            scoreBoardTable.ForeColor = Color.Black;
            scoreBoardTable.AllowUserToAddRows = scoreBoardTable.AllowUserToDeleteRows = scoreBoardTable.AllowUserToOrderColumns = scoreBoardTable.AllowUserToResizeRows = false;
            scoreBoardTable.AutoSizeColumnsMode = DataGridViewAutoSizeColumnsMode.AllCells;
            scoreBoardTable.AutoSizeRowsMode = DataGridViewAutoSizeRowsMode.AllCells;
            scoreBoardTable.RowHeadersVisible = false;
            scoreBoardTable.EnableHeadersVisualStyles = false;
            var style = scoreBoardTable.DefaultCellStyle;
            style.SelectionForeColor = style.SelectionBackColor = Color.Empty;
            style = scoreBoardTable.ColumnHeadersDefaultCellStyle;
            style.SelectionForeColor = style.SelectionBackColor = Color.Empty;
            style.BackColor = Color.Navy;
            style.ForeColor = Color.White;
            style = scoreBoardTable.RowHeadersDefaultCellStyle;
            style.SelectionForeColor = style.SelectionBackColor = Color.Empty;
            style = scoreBoardTable.RowsDefaultCellStyle;
            style.SelectionForeColor = style.ForeColor = Color.Black;
            style.SelectionBackColor = style.BackColor = Color.Yellow;
            style = scoreBoardTable.AlternatingRowsDefaultCellStyle;
            style.SelectionForeColor = style.ForeColor = Color.Black;
            style.SelectionBackColor = style.BackColor = Color.LightGreen;
            scoreBoardTable.CellFormatting += OnScoreBoardCellFormatting;
        }
        private void UpdateScoreBoard()
        {
            scoreBoardTable.ColumnCount = 3 + games.Count;
            for (int c = 0; c < scoreBoardTable.ColumnCount; c++)
            {
                var col = scoreBoardTable.Columns[c];
                if (c == 0)
                {
                    col.Name = "Rank";
                    col.HeaderText = "";
                    col.AutoSizeMode = DataGridViewAutoSizeColumnMode.None;
                    col.Width = 48;
                }
                else if (c == 1)
                {
                    col.Name = "Player";
                    col.HeaderText = "Player";
                    col.DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleLeft;
                }
                else if (c == scoreBoardTable.ColumnCount - 1)
                {
                    col.Name = "Totals";
                    col.HeaderText = "Totals";
                    col.DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleRight;
                    //col.AutoSizeMode = DataGridViewAutoSizeColumnMode.Fill;
                }
                else
                {
                    var game = games[c - 2];
                    col.Name = "Game_" + game.ID;
                    col.HeaderText = game.Name;
                    col.DefaultCellStyle.Alignment = DataGridViewContentAlignment.MiddleRight;
                    //col.AutoSizeMode = DataGridViewAutoSizeColumnMode.DisplayedCells;
                }
            }
            scoreBoardTable.RowCount = players.Count;
            scoreBoardTable.AutoResizeColumnHeadersHeight();
            scoreBoardTable.Invalidate();
        }
        private void OnScoreBoardCellFormatting(object sender, DataGridViewCellFormattingEventArgs e)
        {
            var player = players[e.RowIndex];
            int col = e.ColumnIndex;
            if (col == 0)
                e.Value = "";
            else if (col == 1)
                e.Value = player.Name;
            else if (col == scoreBoardTable.ColumnCount - 1)
                e.Value = player.Total.ToString();
            else
            {
                var game = games[col - 2];
                e.Value = GetScore(player, game).ToString();
            }
            e.FormattingApplied = true;
        }
    }
}

Answer 2

Well, the CellPaint event was the culprit. I was able to achieve what I wanted by negating the CellPaint event, and instead manipulating the controls in the panel so as to have the right background colors as well as size so they fill the grid.

Thank you for all your comments - they were very helpful. As per HighCore's comment, I will now be looking into WPF and I might be able to get something even slicker.