title: ListBox Groupstyle display: How to design a group name?
body: <p>I want to group my items (images) in a ListBox by the date it was created. Then I just use this code:</p>
  
  <pre><code>&lt;ListBox.GroupStyle&gt;
              &lt;GroupStyle /&gt;
  &lt;/ListBox.GroupStyle&gt;
  </code></pre>
  
  <p><strong>BUT</strong> When I tried to apply some style(i.e Border), I got NO group name displayed. ONLY the <strong>Border</strong>
  Here  my new implementation of the groupings using DateTime:</p>
  
  <pre><code>&lt;ListBox.GroupStyle&gt;
              &lt;GroupStyle&gt;
                  &lt;GroupStyle.HeaderTemplate&gt;
                      &lt;DataTemplate&gt;
                          &lt;Border BorderBrush="Gray" BorderThickness="1" CornerRadius="8"&gt;
                              &lt;TextBlock Text="{Binding Path=DateCreated}" FontWeight="Bold" HorizontalAlignment="Center"/&gt;
                          &lt;/Border&gt;
                      &lt;/DataTemplate&gt;
                  &lt;/GroupStyle.HeaderTemplate&gt;
              &lt;/GroupStyle&gt;
          &lt;/ListBox.GroupStyle&gt;
  </code></pre>
  
  <p>Here is my ICollectionView in my MainWindow:    </p>
  
  <pre><code>ICollectionView view = CollectionViewSource.GetDefaultView(CollectedFiles);
          view.GroupDescriptions.Add(new PropertyGroupDescription("DateCreated", new DateTimeToDateConverter()));
          view.SortDescriptions.Add(new SortDescription("FileFullName", ListSortDirection.Ascending));
  </code></pre>
  
  <p><strong>NOTE:</strong> I use DateTimeToDateConverter() converter which returns date without time.</p>