title: Is there a way to find out if a property or variable has been set?
body: <p>As per title, can I find out the history of a property or variable, in terms of whether it has been set or not?</p>
  
  <p>Reason for this is I have some query classes, any properties that have not been set should not be included in the generated query.</p>
  
  <p>Currently I am just trying to add a PropertyInfo instance (I need the name of the property, this is vital to the query generation due to mappings) to a list of properties which have been set in set{}. This is ugly though as it requires more code for what should be classes that only contain properties and no logic (i.e. no removal of stufffrom a list).</p>
  
  <p>Is there something built-in I can use or a more elegant method?</p>