title: Checkbox event that fires AFTER the value has changed
body: <p>I'm creating my very first wpf application.  At this moment I need an event that fires AFTER the value of a checkbox has changed, so checked and unchecked are out of the picture :-(</p>
  
  <p>I have a datagrid, binded to an observable collection.  In this datagrid I have a column with checkboxes (binded to a property in the observ. col.).
  A textbox on the form shows the 'total value' that is the sum of the values of all checked items.  So when a checkbox is checked/unchecked I need to recalculate the total value.  To do this I loop over the items of the observ. col.  However, when I attach the events 'checked' and 'unchecked'.  The total value gets calculated first.  Then the check-value is changed.</p>
  
  <p>Is there a way to have the check value changed and after that fire an event?</p>
  
  <p>Thx,</p>
  
  <p>Jan</p>
  
  <pre><code>&lt;DataGrid AutoGenerateColumns="False" Height="305" Margin="105,137,0,0" Name="GrdReceivings" VerticalAlignment="Top" HorizontalScrollBarVisibility="Visible" VerticalScrollBarVisibility="Visible" ItemsSource="{Binding}" HorizontalAlignment="Left" Width="850" SelectionMode="Single" CanUserAddRows="False" CanUserDeleteRows="False" SelectedCellsChanged="GrdReceivings_SelectedCellsChanged" MouseDoubleClick="GrdReceivings_MouseDoubleClick" IsEnabled="True"&gt;
      &lt;DataGrid.Columns&gt;
              &lt;DataGridCheckBoxColumn MinWidth="40" Binding="{Binding Path=Selected}" &gt;
                  &lt;DataGridCheckBoxColumn.CellStyle&gt;
                      &lt;Style&gt;
                          &lt;EventSetter Event="CheckBox.Checked" Handler="OnCheck"/&gt;
                          &lt;EventSetter Event="CheckBox.Unchecked" Handler="OnUncheck"/&gt;
                      &lt;/Style&gt;
                  &lt;/DataGridCheckBoxColumn.CellStyle&gt;
              &lt;/DataGridCheckBoxColumn&gt;
  ...
  </code></pre>