title: WPF MVVM Listbox of Checkboxes IsChecked not firing on ViewModel when Checked
body: <p>WPF MVVM Listbox of Checkboxes IsChecked not firing on ViewModel when Checked
  The List Box is bound to the ObservableCollection and the Text comes out fine and populates listbox correctly. When it is checked nothing happens. I have tried binding it to a boolean value in the ObservableCollection and a dependency on the view model but neither fire. Any Help would be great. </p>
  
  <p>Update to Question: I am now getting the IsChecked to fire but now I need to grab the content(text(Value in this bind->"Store")) of the checkbox when IsChecked fires. I would settle for the Index of the checkbox that was checked. I have posted code below. 
  Here is my XAML: </p>
  
  <pre><code>&lt;ListBox ItemsSource="{Binding Stores}" SelectedItem="{Binding SelectedItem}" HorizontalAlignment="Center" VerticalAlignment="Top" Width="200" Height="400" SelectionMode="Multiple" IsEnabled="True"&gt;
          &lt;ListBox.ItemTemplate&gt;
              &lt;DataTemplate&gt;
                  &lt;CheckBox IsChecked="{Binding IsChecked,Mode=TwoWay,UpdateSourceTrigger=PropertyChanged}"
                            Content="{Binding Store}"  /&gt;
              &lt;/DataTemplate&gt;
          &lt;/ListBox.ItemTemplate&gt;
      &lt;/ListBox&gt;
  </code></pre>
  
  <p>Here is My MainViewModel:</p>
  
  <pre><code> private IsCheckedViewModel _selectedItem;
      public EbayModel SelectedItem
      {
          get { return _selectedItem; }
          set
          {
              if(_selectedItem!=value)
              {
                  _selectedItem = value;
                  //Need to Grab Content Value when Checkbox is Checked. 
                  //This works when you click on the right side of check box 
                  //but I need the value when IsChecked fires.
                  OnPropertyChanged("SelectedItem");
              }
          }
      }
  
      private ObservableCollection&lt;IsCheckedViewModel&gt; _stores;
      public ObservableCollection&lt;IsCheckedViewModel&gt; Stores
      {
          get { return _stores; }
          set
          {
              if(_stores!=value)
              {
  
                  _stores = value;
                  OnPropertyChanged("Stores");
              }
          }
      }
  </code></pre>
  
  <p>Here is the IsCheckedViewModel(IsChecked works and fires back now)</p>
  
  <pre><code>private string _store;
      public string Store
      {
          get { return _store; }
          set
          {
              if (_store != value)
              {
                  _store = value;
                  OnPropertyChanged("Store");
              }
          }
      }
      private bool _isChecked;
      public bool IsChecked
      {
          get { return _isChecked; }
          set
          {
              if (_isChecked != value)
              {
                  //This works
                  _isChecked = value;
                  OnPropertyChanged("IsChecked");
              }
          }
      }
  </code></pre>