title: UWP InvokeCommandAction on TextBox inside ListView MVVM
body: <p>i have a problem to bind a command in a usercontrol included in a view.</p>
  
  <p>UserControl.xaml</p>
  
  <pre><code>&lt;DataTemplate x:Key="SoldItemDataTemplate" x:DataType="data:SoldItem"&gt;
      &lt;Grid HorizontalAlignment="Stretch"&gt;
          &lt;Grid.ColumnDefinitions&gt;
           ...
          &lt;/Grid.ColumnDefinitions&gt;
           ...
              &lt;TextBox Grid.Column="2" Text="{x:Bind q}"&gt;
                  &lt;Interactivity:Interaction.Behaviors&gt;
                      &lt;Core:EventTriggerBehavior EventName="TextChanged"&gt;
                          &lt;Core:InvokeCommandAction Command="{Binding Path=DataContext.QChanged, ElementName=SoldRows}" CommandParameter="{Binding Mode=TwoWay}"/&gt;
                      &lt;/Core:EventTriggerBehavior&gt;
                  &lt;/Interactivity:Interaction.Behaviors&gt;
              &lt;/TextBox&gt;
          &lt;/Grid&gt;
  &lt;/DataTemplate&gt;
  ...
  &lt;ListView x:Name="SoldRows"
      ItemsSource="{Binding SoldItemsList , Mode=TwoWay}" 
      IsItemClickEnabled="True" 
      ItemTemplate="{StaticResource SoldItemDataTemplate}"&gt;
  ...
  </code></pre>
  
  <p>MainPage.xaml</p>
  
  <pre><code>&lt;Page.DataContext&gt;
      &lt;vm:MainPageViewModel x:Name="ViewModel"&gt;&lt;/vm:MainPageViewModel&gt;
  &lt;/Page.DataContext&gt;
  ...
  &lt;controls:UserControl Grid.Row="1"&gt;&lt;/controls:UserControl&gt;
  ...
  </code></pre>
  
  <p>MainPageViewModel.cs</p>
  
  <pre><code>...
  private DelegateCommand&lt;object&gt; _QSoldChanged;
  ...
  public DelegateCommand&lt;object&gt; QSoldChanged
      {
          get
          {
              if (_QSoldChanged == null)
              {
                  _QSoldChanged = new DelegateCommand&lt;object&gt;((object par) =&gt;
                  {
                      ...
                  });
              }
  
              return _QSoldChanged;
          }
      }
  </code></pre>
  
  <p>So, i'd like to call QSoldChanged, on TextChanged event, but nothing happens. What am i missing? Is that the right way to set command in this case?
  If you need more just ask!
  Thanks in advance</p>