title: How to prevent T4 (.tt) template from being generated upon programmatic condition
body: <p>I am using Visual Studio 2010 <strong>TextTemplatingFileGenerator</strong> custom tool to generate C# code (.cs) and would like to know if is there a way of preventing a given .tt from being completely generated upon a given programmatic condition.</p>
  
  <p>I want to achieve the following:</p>
  
  <ul>
  <li>Sometimes I want to generate a regular editable class;</li>
  <li>Other times I want to generate a pair of classes to represent a parent-child relation, each of them implementing their specific set of rules required by their role.</li>
  </ul>
  
  <p>Before answering, please bear in mind that <strong>DO NOT</strong> intend to use <strong>TextTemplatingFilePreprocessor</strong> - I already have explored its strengths and weaknesses. Although is suitable for other scenarios, is not for my current context. So I really want to stick to <strong>TextTemplatingFileGenerator</strong>.</p>