c# - Draw borders around some cells in a tablelayoutpanel

Question

Don't ask why but I have the requirement to draw a border around certain cells in a TableLayoutPanel.

For example, for simplicity, lets say I have a 1 row, 5 column TableLayoutPanel. Each cell has a button in it. I would like to draw a box around the first 3 cells and then another box around the last 2 cells. So two boxes total.

Any suggestions on how to accomplish that?

Thanks.

Answer 1

You could use CellPaint event and draw the border rectangle when needed:

tableLayoutPanel1.CellPaint += tableLayoutPanel1_CellPaint;

The handler:

void tableLayoutPanel1_CellPaint(object sender, TableLayoutCellPaintEventArgs e)
{
    if (e.Column == 1 && e.Row == 0)
        e.Graphics.DrawRectangle(new Pen(Color.Blue), e.CellBounds);
}

You can draw any kind of border using ControlPaint:

if (e.Column == 1 && e.Row == 0)
{
    var rectangle = e.CellBounds;
    rectangle.Inflate(-1, -1);

    ControlPaint.DrawBorder3D(e.Graphics, rectangle, Border3DStyle.Raised, Border3DSide.All); // 3D border
    ControlPaint.DrawBorder(e.Graphics, rectangle, Color.Red, ButtonBorderStyle.Dotted); // dotted border
}