title: Get current line's text (where the caret is blinking) of richtextbox
body: <p>I really need to get the contents of the line where the caret is blinking in a rich text box control. Suppose I have the following text in a rich text box:</p>
  
  <pre><code>This
  is
  a
  test
  </code></pre>
  
  <p>I would like to retrieve the text of line 2 by providing its index (for example 2 or 1 if the function is zero-based).</p>
  
  <p>Thanks in advance, </p>
  
  <p>Vali</p>