title: Universal Apps MessageBox: "The name 'MessageBox' does not exist in the current context"
body: <p>I want to use MessageBox for showing download errors in my WP8.1 app.</p>
  
  <p>I added:</p>
  
  <pre><code>using System.Windows;
  </code></pre>
  
  <p>but when I type:</p>
  
  <pre><code>MessageBox.Show("");
  </code></pre>
  
  <p>I get error:</p>
  
  <pre><code>"The name 'MessageBox' does not exist in the current context"
  </code></pre>
  
  <p>In Object Browser I found that such class should exist and in "Project->Add reference... ->Assemblies->Framework" is shown that all assemblies are referenced.</p>
  
  <p>Do I miss something? Or is there another way how to show something like messagebox?</p>