title: WPF Button IsEnabled Check on Multiple Bindings
body: <p>I have the IsEnabled property of a XAML button configured with the following databinding currently:</p>
  
  <pre><code>&lt;Button Name="ThirdPartyPostoneButton" Content="Postpone"
          Click ="postponeThirdPartyUpdatesButton_Click" Margin="5,5,0,0"
          Height="25" IsEnabled="{Binding Item3.CanDefer}"/&gt;
  </code></pre>
  
  <p>I need to also add a check for <code>IsEnabled="{Binding Item3.InstallSourceExists}"</code> (in other words both criteria must be met in order for the button to be enabled). How can I accomplish this?</p>