title: How to check passed int parameter
body: <p>This was more complicated than I thought! It's easy to check if a string is empty or null, but how is this done with an int? Perhaps equal easy, but I'm stuck!</p>
  
  <p>I pass an int from a html form input field to an action method in the controller, but despite all combinations I try, nothing works! It seems that <code>!</code> is not possible to use with an int. First of all, could an int be null? </p>
  
  <p>What I want to check if a user has clicked the submit button without entered a number. I also want to check if it's an int and not a string? Some help is appreciated!</p>