title: WPF DatePicker not updating datasource
body: <p>I have a WPF datagrid (I'm actually using Xceed DataGrid but I think the binding still works the same). I have a DatePicker column in my grid, but when I select a date, it doesn't update my underlying datasource. Any ideas?</p>
  
  <p>I've already tried:</p>
  
  <pre><code>{Binding Path=., Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}
  {Binding Path=., Mode=TwoWay}
  {Binding Path=., UpdateSourceTrigger=PropertyChanged}
  {Binding Path=.}
  {Binding .}
  {Binding}
  </code></pre>
  
  <p>XAML:</p>
  
  <pre><code>&lt;xcdg:Column FieldName="NeedDateOverride" Title="NEED DATE (OVERRIDE)" Width="100"&gt;
      &lt;xcdg:Column.CellContentTemplate&gt;
          &lt;DataTemplate x:Name="needDateOverrideTemplate"&gt;
              &lt;DockPanel HorizontalAlignment="Stretch" LastChildFill="True"&gt;
                  &lt;DatePicker SelectedDate="{Binding Path=., Mode=TwoWay, UpdateSourceTrigger=PropertyChanged}" SelectedDateChanged="NeedDateOverride_SelectedDateChanged" PreviewMouseDown="NeedDateOverride_GotFocus" CalendarOpened="NeedDateOverride_CalendarOpened"&gt;&lt;/DatePicker&gt;
              &lt;/DockPanel&gt;
          &lt;/DataTemplate&gt;
      &lt;/xcdg:Column.CellContentTemplate&gt;
  &lt;/xcdg:Column&gt;
  </code></pre>
  
  <p>C#:</p>
  
  <pre><code>public DateTime NeedDateOverride
  {
      get
      {
          return this.needDateOverrideValue;
      }
  
      set
      {
          if (value != this.needDateOverrideValue)
          {
              this.needDateOverrideValue = value;
              NotifyPropertyChanged();
          }
      }
  }
  </code></pre>