Integral Number of Text Lines in RichTextBox

Hello,

I would like to set up a RichTextBox so that the text
shows an integral number of text lines when the text box
is scrolled all the way down. How can this be done?

I tried this: I set ClientSize.Height to be a multiple of
Font.Height, verify that it's set, but I get slightly
fewer than the expected number of lines. This means that
when the text box is scrolled all the way down, part of a
line shows at the top, which looks bad.


using System;
using System.Drawing;
using System.Text;
using System.Windows.Forms;



class TextBoxTesterForm : Form
{
public TextBoxTesterForm()
{
d_rtb = new RichTextBox();
d_rtb.SuspendLayout();
d_rtb.Parent = this;
d_rtb.Location = new Point(10,10);
int desiredTextHeight = lines * d_rtb.Font.Height;
d_rtb.ClientSize = new Size(200, desiredTextHeight);
d_rtb.ResumeLayout();
Console.WriteLine("lines={0}", lines);
Console.WriteLine("rtb Font.Height = {0}",
d_rtb.Font.Height);
Console.WriteLine("rtb Font.GetHeight() = {0}",
d_rtb.Font.GetHeight());
Console.WriteLine("desiredTextHeight = {0}",
desiredTextHeight);
Console.WriteLine("rtb ClientSize = {0}",
d_rtb.ClientSize);
Console.WriteLine("rtb DisplayRectangle = {0}",
d_rtb.DisplayRectangle);
Console.WriteLine("rtb Size = {0}", d_rtb.Size);
Console.WriteLine("rtb Multiline = {0}", d_rtb.Multiline);
}

RichTextBox d_rtb;
int lines = 5;
}

class TextBoxTestMain {
static void Main()
{ Application.Run(new TextBoxTesterForm()); }
}