C# tablelayoutpanel unable to remove padding/margin

Question

Basically I'm facing a problem with removing the padding/margin between controls in a tablelayoutpanel.

I've set the tablelayoutpanel margin and padding to 0. Cellborderstyle is none.

Added controls are all set to 0 for margin and padding.

Yet that mysterious margin keeps appearing. Any help?

Tried this 2 solutions here and various other on the web but none could remove that spacing in between.

• Remove spacing between cells in tablelayoutpanel in Windows form?

• Is there any way to control thickness of cell border in TableLayoutPanel?

Running on VS2010, .net 4.5

Form1.cs

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace Multiply {
    public partial class Form1 : Form {
        public Form1() {
            InitializeComponent();
            LoadBoard(10, 10);
        }

    private void LoadBoard(int col, int row) {
        board.ColumnCount = col;
        board.RowCount = row;
        board.BorderStyle = BorderStyle.FixedSingle;

        float colSize = 100f / col;
        float rowSize = 100f / row;

        board.ColumnStyles[0].SizeType = SizeType.Percent;
        board.ColumnStyles[0].Width = colSize;
        board.RowStyles[0].SizeType = SizeType.Percent;
        board.RowStyles[0].Height = rowSize;


        for (int x = 0; x < col; x++)
            board.ColumnStyles.Add(new ColumnStyle(SizeType.Percent, colSize));

        for (int x = 0; x < row; x++) {
            board.RowStyles.Add(new RowStyle(SizeType.Percent, rowSize));
            for (int y = 0; y < col; y++) {
                board.Controls.Add(CreateButton( x + "," + y ), y, x);
            }
            Console.WriteLine(x);
        }

    }

    private Button CreateButton(string text) {
        Button a = new Button();
        a.Text = text;
        a.Dock = DockStyle.Fill;
        a.Margin = new Padding(0);
        a.Padding = new Padding(0);
        return a;
    }
}
}

Designer

namespace Multiply {
    partial class Form1 {
        /// <summary>
        /// Required designer variable.
        /// </summary>
        private System.ComponentModel.IContainer components = null;

        /// <summary>
        /// Clean up any resources being used.
        /// </summary>
        /// <param name="disposing">true if managed resources should be disposed; otherwise, false.</param>
        protected override void Dispose(bool disposing) {
            if (disposing && (components != null)) {
                components.Dispose();
            }
            base.Dispose(disposing);
        }

        #region Windows Form Designer generated code

        /// <summary>
        /// Required method for Designer support - do not modify
        /// the contents of this method with the code editor.
        /// </summary>
        private void InitializeComponent() {
            this.board = new System.Windows.Forms.TableLayoutPanel();
            this.SuspendLayout();
            // 
            // board
            // 
            this.board.ColumnCount = 1;
            this.board.ColumnStyles.Add(new System.Windows.Forms.ColumnStyle(System.Windows.Forms.SizeType.Percent, 25F));
            this.board.Dock = System.Windows.Forms.DockStyle.Top;
            this.board.Location = new System.Drawing.Point(0, 0);
            this.board.Margin = new System.Windows.Forms.Padding(0);
            this.board.Name = "board";
            this.board.RowCount = 1;
            this.board.RowStyles.Add(new System.Windows.Forms.RowStyle(System.Windows.Forms.SizeType.Absolute, 20F));
            this.board.Size = new System.Drawing.Size(368, 223);
            this.board.TabIndex = 0;
            // 
            // Form1
            // 
            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
            this.ClientSize = new System.Drawing.Size(368, 391);
            this.Controls.Add(this.board);
            this.Name = "Form1";
            this.Text = "Form1";
            this.ResumeLayout(false);

        }

        #endregion

        private System.Windows.Forms.TableLayoutPanel board;
    }
}

Answer 1

You are chasing the wrong problem, this gap is caused by the Button control, not the TableLayoutPanel. Something you can clearly see when you drop a button on the form with the designer, note the gap between the selection rectangle and the button surface.

You'll need to tinker with the button to get rid of it or use a different kind of control. Simplest way is to make it flat:

    private Control CreateButton(string text) {
        var a = new Button();
        a.FlatStyle = FlatStyle.Flat;
        a.FlatAppearance.BorderSize = 0;   // optional
        // etc...
    }

Remove the BorderSize assignment if you want to see a grid.