title: Unique random numbers in listbox
body: <p>I was wondering how can I get 8 unique random numbers in my listbox, code so far:</p>
  
  <pre><code>lbLeft.Items.Clear();
  Random rnd = new Random();
  int n = rnd.Next();
  int x = 8;
  
  do
  {
      lbL.Items.Add(rnd.Next(0, 20));
  
  } while ((lbLeft.Items.Count != x));
  </code></pre>
  
  <p>It is filling the listbox with 8 random numbers, but I need them unique.</p>
  
  <p>Any help would be greatly appreciated,</p>