title: How to add paragraph and then a line?
body: <p>All of the examples I have seen so far using ITextSharp start from scratch and create a new document, add something to it and close it.
  What if I need to do multiple things to a PDF for example I want to add a paragraph and then add a line. 
  For example if I run this simple console app in which I just create a PDF and add a paragraph and then close it everything runs fine.</p>
  
  <pre><code>class Program
  {
      static void Main(string[] args)
      {
          Document pdfDoc = new Document();
          PdfWriter.GetInstance(pdfDoc, new FileStream("TestPDF.pdf", FileMode.Create));
          pdfDoc.Open();
  
          pdfDoc.Add(new Paragraph("Some Text added"));
  
          pdfDoc.Close();
  
          Console.WriteLine("The file was created.");
          Console.ReadLine();
      }
  }
  </code></pre>
  
  <p>However if I need to do something else like draw a line like this</p>
  
  <pre><code>class Program
  {
      static void Main(string[] args)
      {
          Document pdfDoc = new Document();
          PdfWriter.GetInstance(pdfDoc, new FileStream("TestPDF.pdf", FileMode.Create));
          pdfDoc.Open();
  
          pdfDoc.Add(new Paragraph("Some Text added"));
  
          PdfWriter writer = PdfWriter.GetInstance(pdfDoc, new FileStream("TestPDF.pdf", FileMode.OpenOrCreate));
          PdfContentByte cb = writer.DirectContent;
          cb.MoveTo(pdfDoc.PageSize.Width / 2, pdfDoc.PageSize.Height / 2);
          cb.LineTo(pdfDoc.PageSize.Width / 2, pdfDoc.PageSize.Height);
          cb.Stroke();
          writer.Close();
  
          pdfDoc.Close();
  
          Console.WriteLine("The file was created.");
          Console.ReadLine();
      }
  }
  </code></pre>
  
  <p>I get an error when trying to open the file because it is already opened by pdfDoc.
  If I put the highlighted code after the pdfDoc.Close() I get an error saying "The Document is not opened"
  How do I switch from adding text to adding a line?
  Do I need to close the doc and then re-open it again with the PDFReader and modify it there or can I do it all at once?</p>