How to override the behavior of the backspace key?

Question

C++ / C#

There is a form on Windows, in it richTextBox.
You need to make sure that the backspace key deletes a character in this control into a special buffer

Answer 1

private void richTextBox1_PreviewKeyDown(object sender, PreviewKeyDownEventArgs e)
        {
            if (e.KeyCode == Keys.Back) {
                char s = richTextBox1.Text[richTextBox1.TextLength - 1];
                MessageBox.Show(s.ToString());
                // или копируем символ s в специальный буфер
            }
        }