title: How to use Conditional Compilation in Windows Universal App
body: <p>I'm using VS 2017 to implement an app that shares code between Windows form and Universal Windows App. </p>
  
  <p>In project properties I see conditional compilation symbols as below:</p>
  
  <p><a href="https://i.stack.imgur.com/L3DAb.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/L3DAb.png" alt="project properties"></a></p>
  
  <p>When I use below code</p>
  
  <pre><code>#if WINDOWS_UWP
      // code for Windows Universal App
  #else
      // code for Windows Form
  #endif
  </code></pre>
  
  <p>program executes the Windows Form code not the UWP code.</p>
  
  <p>What I'm doing wrong here?</p>