title: Regex must contain specific letters in any order
body: <p>I have been attempting to validate a string in VB.net that must contain these three letters in no particular order and do not need to be next to One another. ABC</p>
  
  <p>I can do this easily using LINQ</p>
  
  <pre><code>MessageBox.Show(("ABC").All(Function(n) ("AAAABBBBBCCCC").Contains(n)).ToString)
  </code></pre>
  
  <p>However, after searching Google and SO for over a week, I am completely stumped. My closest pattern is <code>".*[A|B|C]+.*[A|B|C]+.*[A|B|C]+.*"</code> how ever <code>AAA</code> would also return true. I know i can do this using other methods just after trying for a week i really want to know if its possible using One regular expression.</p>