title: How to set project wide #define in C#
body: <p>I have several classes in a project which need to only be in certain builds of the application which are currently not ready for release or debug.</p>
  
  <p>To prevent these classes from being used, I want to set around them this:</p>
  
  <pre><code>#if USE_MYCLASS
  // Code here...
  #endif
  </code></pre>
  
  <p>Unfortunately, I don't know how to setup a project-wide #define.</p>
  
  <p>Is there functionality in Visual Studio to set project-wide definitions?</p>
  
  <p>If there is, though I don't need it right now, is there a functionality to set solution-wide definitions?</p>
  
  <p>If there is no functionality for such (seeing as C# does not have include files, I suppose it's possible), is there any method or plugin of doing this functionality without using the command line compiler and /D?</p>