Limit the max number of chars per line in a textbox

Question

Say I have the following:

Answer 1

I know this is an extremely late answer, but so that people who find this can get a good answer, with protection against for instance Ctrl+C and stuff:

private void textBox1_TextChanged(object sender, EventArgs e)
{
    foreach (string line in textBox1.Lines)
    {
        if (line.Length > 60)
        {
            textBox1.Undo();
        }
    }

    textBox1.ClearUndo();
}

Note that this does mean you cannot use Ctrl+Z in the textbox anymore but if that doesn't bother you this is a good option, because it works with any font.

EDIT This doesn't work with wpf textboxes, only windows forms textboxes