title: how to set Listpicker items where SelectionMode is multiple
body: <p>In my WP8 app, i am using the ListPicker control with multi selection option. In my page, i am loading the Listpicker data from a List of custom classes. And i can able to save what objects are user selected based by implementing the SummaryForSelectedItemsDelegate event and i am saving this info to Isolated storage for later access.</p>
  
  <p>My main problem, how to select the above user selected option when user opened this page where this list picker is there?</p>
  
  <p>I tried using the SelectionChanged event and try to select the object based on stored data, it didn't worked.</p>
  
  <pre><code>&lt;toolkit:ListPicker x:Name="userCountryList" ItemsSource="{Binding CountryList}"  Header="Choose a country or region:"  SelectionMode="Multiple" FullModeItemTemplate="{StaticResource DataTemplate2}" /&gt;
  
  &lt;phone:PhoneApplicationPage.Resources&gt;
  &lt;DataTemplate x:Key="DataTemplate2"&gt;
      &lt;StackPanel Orientation="Horizontal"&gt;
         &lt;TextBlock HorizontalAlignment="Left"  FontSize="28" TextWrapping="Wrap" Text="{Binding CountryName}" VerticalAlignment="Center" Width="Auto"/&gt;
      &lt;/StackPanel&gt;
  &lt;/DataTemplate&gt;
  </code></pre>
  
  <p></p>
  
  <p>Code behind:</p>
  
  <pre><code>var brushes = new List&lt;CustomClass&gt;();
  brushes.Add(new CustomClass { CountryCode = "US", CountryName = "United States" });
  brushes.Add(new CustomClass { CountryCode = "FR", CountryName = "France" });
  brushes.Add(new CustomClass { CountryCode = "DE", CountryName = "Germany" });
  brushes.Add(new CustomClass { CountryCode = "CA", CountryName = "Canada" });
  
  userCountryList.SummaryForSelectedItemsDelegate = SummarizeItems;
  userCountryList.ItemsSource = brushes;
  
  
  private string SummarizeItems(IList items)
      {
          if (items != null &amp;&amp; items.Count &gt; 0)
          {
              string summarizedString = "";
  
              if (items != null)
                  for (int i = 0; i &lt; items.Count; i++)
                  {
                      summarizedString += ((CustomClass )items[i]).CountryCode;
  
                      // If not last item, add a comma to seperate them
                      if (i != items.Count - 1)
                          summarizedString += ", ";
                  }
  
              if (!AppSettings.Default.UserSelectedMarkets.Equals(summarizedString))
                  AppSettings.Default.UserSelectedMarkets = summarizedString;
  
              return summarizedString;
          }
          else
              return "Nothing selected";
      }
  </code></pre>