title: VSTS Xamarin.iOS build tasks define multiple constants using /p:DefineConstants
body: <p>I'm using the Xamarin.iOS build task in VSTS to build my solution.
  I want to define the constants <code>ENABLE_ANALYTICS</code> and <code>ENV_DEV</code>. </p>
  
  <p>Unfortulately, I can't figure out what to enter in the <code>Arguments</code> input field to get it run successfully. I'm using the <code>Hosted macOS Preview</code> build agent and <code>msbuild (Visual Studio for Mac)</code> build tool.</p>
  
  <p><strong>I tried:</strong></p>
  
  <p><code>/p:DefineConstants=ENABLE_ANALYTICS;ENV_DEV</code></p>
  
  <blockquote>
    <p>MSBUILD : error MSB1006: Property is not valid.</p>
    
    <p>Switch: ENV_DEV</p>
  </blockquote>
  
  <p><code>/p:DefineConstants="ENABLE_ANALYTICS;ENV_DEV"</code></p>
  
  <blockquote>
    <p>MSBUILD : error MSB1006: Property is not valid.</p>
    
    <p>Switch: ENV_DEV</p>
  </blockquote>
  
  <p><code>/p:DefineConstants='ENABLE_ANALYTICS;ENV_DEV'</code></p>
  
  <blockquote>
    <p>MSBUILD : error MSB1006: Property is not valid.</p>
    
    <p>Switch: ENV_DEV'</p>
  </blockquote>
  
  <p><code>/p:DefineConstants=""ENABLE_ANALYTICS;ENV_DEV""</code></p>
  
  <blockquote>
    <p>MSBUILD : error MSB1006: Property is not valid.</p>
    
    <p>Switch: ENV_DEV</p>
  </blockquote>
  
  <p><code>'/p:DefineConstants=""ENABLE_ANALYTICS;ENV_DEV"'</code></p>
  
  <blockquote>
    <p>MSBUILD : error MSB1008: Only one project can be specified.</p>
    
    <p>Switch: '/p:DefineConstants=ENABLE_ANALYTICS;ENV_DEV'</p>
  </blockquote>