title: Preventing duplicate matches in RegEx
body: <p>The following code</p>
  
  <pre><code>string expression = "(\\{[0-9]+\\})";
  RegexOptions options = ((RegexOptions.IgnorePatternWhitespace | RegexOptions.Multiline) | RegexOptions.IgnoreCase);
  Regex tokenParser = new Regex(expression, options);
  
  MatchCollection matches = tokenParser.Matches("The {0} is a {1} and the {2} is also a {1}");
  </code></pre>
  
  <p>will match and capture "{0}", "{1}", "{2}" and "{1}".</p>
  
  <p>Is it possible to change it (either the regular expression or option of the RegEx) so that it would match and capture "{0}", "{1}" and "{2}". In other words, each match should only be captured once?</p>