title: WPF&MVVM: Library System.Windows.Interactivity in not available anymore?
body: <p>I need to add <code>System.Windows.Interactivity.dll</code> library via <code>Reference Manager</code>. In <code>Visual Studio 2017</code>, I did not find it. All search results that begins from <code>System.Windows</code> showed on the screenshot below:</p>
  
  <p><a href="https://i.stack.imgur.com/aY6Ba.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/aY6Ba.png" alt="enter image description here"></a></p>
  
  <p>I thought that this library becomes build-in in WPF project of current Visual Studio version, so when I added the bellow <code>C#</code> code, no warnings from IDE has been displayed:</p>
  
  <pre><code>private RelayCommand doubleCommand;
  public RelayCommand DoubleCommand {
      get {
          return doubleCommand ??
          (doubleCommand = new RelayCommand(obj =&gt; {
              Phone phone = obj as Phone;
              if (phone != null) {
                  Phone phoneCopy = new Phone {
                      Company = phone.Company,
                      Price = phone.Price,
                      Title = phone.Title
                  };
                  Phones.Insert(0, phoneCopy);
              }
          }));
      }
  }
  </code></pre>
  
  <p>However, when I added the following <code>XAML</code> markup, it says that <code>Interaction</code>, <code>EventTrigger</code> and <code>InvokeCommandAction</code> has not been found in <code>clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity</code> namespace:</p>
  
  <pre><code>&lt;Window x:Class="MVVM_Tutorial.MainWindow"
          xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
          xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
          xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
          xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
          xmlns:local="clr-namespace:MVVM_Tutorial"
          xmlns:i="clr-namespace:System.Windows.Interactivity;assembly=System.Windows.Interactivity"
          mc:Ignorable="d"
          Title="MainWindow" Height="350" Width="525"&gt;
  
  &lt;!-- ... --&gt;
  
      &lt;Button Content="2x"&gt;
          &lt;i:Interaction.Triggers&gt;
              &lt;i:EventTrigger EventName="MouseDoubleClick"&gt;
                  &lt;i:InvokeCommandAction
                      Command="{Binding DoubleCommand}"
                      CommandParameter="{Binding SelectedPhone}" /&gt;
              &lt;/i:EventTrigger&gt;
          &lt;/i:Interaction.Triggers&gt;
      &lt;/Button&gt;
  
  &lt;!-- ... --&gt;
  
  &lt;/Window&gt;
  </code></pre>
  
  <p>Has it relationship with <code>System.Windows.Interactivity</code> library or no, what have I do to solve this problem?</p>