title: MultiBinding for list items
body: <pre><code>&lt;MultiBinding Converter="{StaticResource DifferenceConverter}"&gt;
          &lt;Binding Path="[1].Value" /&gt;
          &lt;Binding Path="[0].Value" /&gt;
  &lt;/MultiBinding&gt;
  </code></pre>
  
  <p>I have list <code>List&lt;List&lt;KeyValuePair&lt;string, int&gt;&gt;&gt;</code> which i bind to <code>DataContext</code> of WPF Toolkit chart. </p>
  
  <p>Every item in list - new <code>ColumnSerie</code> and binding I try to apply only to last serie</p>
  
  <p>What i need - correctly use MultiBinding (Don't know how to write correct path to values of first and second items in list).</p>
  
  <p>Also tried smth like <code>[1]/Value</code> - unsuccess.</p>
  
  <hr>
  
  <p>UPDATE (Detailed Explanation): </p>
  
  <p>As i wrote before, i have chart with few columnSeries (really only 2). 
  I bind <code>List&lt;List&lt;KeyValuePair&lt;string, int&gt;&gt;&gt;</code> (size = 2) to chart <code>DataContext</code> and in XAML init ColumnSeries like <code>ItemsSource="{Binding [1]}"</code></p>
  
  <p>For Second ColumnSeries I create Style : </p>
  
  <pre><code>&lt;Style x:Key="ColumnDataPointStyle1" TargetType="{x:Type chartingToolkit:ColumnDataPoint}"&gt;
          &lt;Setter Property="Background" Value="#61596f" /&gt;
          &lt;Setter Property="BorderBrush" Value="#61596f" /&gt;
          &lt;Setter Property="BorderThickness" Value="100" /&gt;
          &lt;Setter Property="IsTabStop" Value="False" /&gt;
          &lt;Setter Property="Padding" Value="0" /&gt;
          &lt;Setter Property="Margin" Value="0"/&gt;
          &lt;Setter Property="Template"&gt;
              &lt;Setter.Value&gt;
                  &lt;ControlTemplate TargetType="{x:Type chartingToolkit:ColumnDataPoint}"&gt;
                      &lt;Grid&gt;
                          &lt;Rectangle Fill="{TemplateBinding Background}" /&gt;
                          &lt;TextBlock  Foreground="White" FontSize="8" FontWeight="Bold" HorizontalAlignment="Center" VerticalAlignment="Center"&gt; 
                              &lt;TextBlock.Text&gt;
                                  &lt;MultiBinding Converter="{StaticResource DifferenceConverter}"&gt;
                                      &lt;Binding ElementName="FirstScan" Path="ItemsSource[0].Value"/&gt;
                                      &lt;Binding Path="Value" /&gt;
                                  &lt;/MultiBinding&gt;
                              &lt;/TextBlock.Text&gt;   
                          &lt;/TextBlock&gt;
                      &lt;/Grid&gt;
                  &lt;/ControlTemplate&gt;
              &lt;/Setter.Value&gt;
          &lt;/Setter&gt;
      &lt;/Style&gt;
  </code></pre>
  
  <p>And Converter : </p>
  
  <pre><code>public class DifferenceConverter : IMultiValueConverter
  {
      public object Convert(object[] values, Type targetType, object parameter, CultureInfo culture)
      {
          var diff = (int) values[1] - (int) values[0];
          if (diff &gt; 0)
          {
              return "&lt;";
          }
          if (diff &lt; 0)
          {
              return "&gt;";
          }
          return "none";
      }
  
      public object[] ConvertBack(object value, Type[] targetTypes, object parameter, CultureInfo culture)
      {
          throw new NotImplementedException();
      }
  }
  </code></pre>
  
  <p>This converter should show difference between column value in first and second series. If first value is greater than second - ">" else "&lt;", if Equal - "none" etc. 
  Problem - need to bind values from first ColumnSeries.</p>