Pie Chart XAML Binding

I am using MVVM and SL4. I have a collection of VoteResults that are being bound to a ItemsControl. I want a PieChart in EACH VoteResult item. A VoteResult item object properties looks like this: VotedYes 10; VotedNo 4; Abstained 2; DidntVote 6;

How can I pass these VoteItem property values to build the pie chart's series ItemSource in XAML? So开发者_如何学Cmething like :

 <charting:Chart>
    <charting:Chart.Series>
       <charting:PieSeries>
          <charting:PieSeries.ItemsSource>
             <controls:ObjectCollection>

             </controls:ObjectCollection>
          </charting:PieSeries.ItemsSource>
       </charting:PieSeries>
    </charting:Chart.Series>
 </charting:Chart>

The charting controls are designed to present data that has been processeda and aggregated ready for presentation.

Sounds to me like you want a PieSeries to present a series that contains the Categories "VotedYes", "VotedNo", "Abstained" and "Did not vote" as its independent value and a vote count as the dependant value. In that case you need to pass to the ItemsSource a collection containing this set of data, a single object will not do.

You will need to pass the VoteResult object through a function that returns something like IEnumerable<KeyValuePair<String, Int32>>.

 public IEnumerable<KeyValuePair<String, Int32>> ProcessVoteResult(VoteResult vr)
 {
      yield return new KeyValuePair<String, In232>("Voted Yes", vr.VotedYes);
      yield return new KeyValuePair<String, In232>("Voted No", vr.VotedNo);
      yield return new KeyValuePair<String, In232>("Abstained", vr.Abstained);
      yield return new KeyValuePair<String, In232>("Did Not Vote ", vr.DidntVote );
 }

Now you will probably want to bind the VoteResult since you appear to be using MVVM (from looking at your other questions). You you will need a value converter:-

 public class VoteResultToEnumerableConverter
 {
    public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
         if (value != null)
         {
              return ProcessVoteResult((VoteResult)value);
         }
         return null;
    }

    public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
    {
         throw new NotImplementedException();
    }
 }

You would then have this converter in a static resources somewhere above the chart:-

 <local:VoteResultToEnumerableConverter x:Key="vrconv" />

Then your chart would look like:-

 <toolkit:Chart>
     <toolkit:PieSeries
         ItemsSource="{Binding SomeVoteResult, Converter={StaticResource vrconv}}"
         DependentValuePath="Key"
         IndependendValuePath="Value"/>
 </toolkit:Chart>