title: How do you multi-target a .NET Core class library with csproj?
body: <p>When .NET Core still used the <code>project.json</code> format, you could build a class library <a href="https://blogs.msdn.microsoft.com/cesardelatorre/2016/06/28/running-net-core-apps-on-multiple-frameworks-and-what-the-target-framework-monikers-tfms-are-about/" rel="noreferrer">targeting multiple frameworks</a> (e.g. net451, netcoreapp1.0).</p>
  
  <p>Now that the official project format is <code>csproj</code> using MSBuild, how do you specify multiple frameworks to target? I am trying to look for this from the project settings in VS2017, but I am able to only target a single framework from the .NET Core frameworks (it doesn't even list the other full .NET Framework versions which I <em>do</em> have installed):</p>
  
  <p><a href="https://i.stack.imgur.com/fF4eA.png" rel="noreferrer"><img src="https://i.stack.imgur.com/fF4eA.png" alt="enter image description here"></a></p>