title: Using FluentValidation to check if a string is a number greater than zero
body: <p>I've started using <code>FluentValidation</code> on a WPF project, till now I used it in a simple way checking if a field has been filled or less then n character.</p>
  <p>Now I've to check if the value inserted (which is a string...damn old code) is greater then 0. Is there a simple way I can convert it using</p>
  <pre><code>RuleFor(x=&gt;x.MyStringField).Somehow().GreaterThen(0) ?
  </code></pre>
  <p>Thanks in advance</p>