Grouping ListBox with Date
<p>I have no idea how to achieve this, but I have a date and time column in a ListBox. The Date column should not display if the date was already in there. I know that in combination with ListCollectionView and Listview/DataGrids, it is propably possible. But can I achieve this with a ListBox and a List. Keep in mind I am using the MVVM principle. This is my listbox:</p>

<pre><code>&lt;ListBox Grid.Row="2" ScrollViewer.HorizontalScrollBarVisibility="Disabled" ItemsSource="{Binding Schedules}"&gt;
                &lt;ListBox.ItemTemplate&gt;
                    &lt;DataTemplate&gt;
                        &lt;StackPanel Background="Transparent"&gt;
                            &lt;Grid Background="Transparent"&gt;
                                &lt;Grid.ColumnDefinitions&gt;
                                    &lt;ColumnDefinition  Width="100"/&gt;
                                    &lt;ColumnDefinition  Width="100"/&gt;
                                    &lt;ColumnDefinition/&gt;
                                &lt;/Grid.ColumnDefinitions&gt;
                                &lt;Grid.RowDefinitions&gt;
                                    &lt;RowDefinition/&gt;
                                &lt;/Grid.RowDefinitions&gt;
                                &lt;TextBlock Grid.Column="0" Grid.Row="0"  Text="{Binding MyDateTime, StringFormat='d' }" HorizontalAlignment="Left"  VerticalAlignment="Center"/&gt;
                                &lt;TextBlock Grid.Column="1" Grid.Row="0"  Text="{Binding MyDateTime, StringFormat='t'}" HorizontalAlignment="Left"  VerticalAlignment="Center"/&gt;
                                &lt;TextBlock Grid.Column="2" Grid.Row="0"  Text="{Binding SomeText}"  TextTrimming="WordEllipsis" LineStackingStrategy="MaxHeight" MaxHeight="20" HorizontalAlignment="Left"  VerticalAlignment="Center"/&gt;
                            &lt;/Grid&gt;
                        &lt;/StackPanel&gt;
                    &lt;/DataTemplate&gt;
                &lt;/ListBox.ItemTemplate&gt;
            &lt;/ListBox&gt;
</code></pre>

<p>I have made this in excel to give an example of what I am trying to achieve:
<a href="https://i.stack.imgur.com/QiuNo.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/QiuNo.png" alt="enter image description here"></a></p>

<p>I want the affect where I have highlighted with yellow</p>