title: ObservableCollection<T> not updating the UI
body: <p>So I have an observable collection that I am updating and I can see the values have changed but the UI is not changing.  Here is what I have</p>
  
  <pre><code>public static class GeoLocations
  {
  
      public static ObservableCollection&lt;Station&gt; _locations = new ObservableCollection&lt;Station&gt;();
      public static ObservableCollection&lt;Station&gt; locations
      {
          get { return _locations; }
          set 
          { 
              _locations = value;      
          }
      }
  }
  
  public class Station
  {
      public int StationNumber { get; set; }
      // Bunch more properties here ...
  }
  </code></pre>
  
  <p>Then I have a class that is generating random numbers for all the properties in another thread.  I know that its changing them because when I hover over the items in the chart I'm using I see it updating.  However the chart itself is not updating.  Let say that the first number is 1.6.  Then updates to 1.4 0.5 1.2... The chart remains at 1.6.   </p>
  
  <p>The chart I'm using is an Infragistics XamDataChart.  I suspect the problem is the way I've implemented my classes.  I have more UI that need to be updated than just the charts so I'm hoping once I figure this out I can make those work here.  </p>
  
  <p>Here is my xaml for the XamDataChart</p>
  
  <pre><code>&lt;ig:XamDataChart Style="{StaticResource BarChartStyle}" Grid.Row="1" Grid.Column="1"&gt;
  
          &lt;ig:XamDataChart.Axes&gt;
              &lt;ig:NumericYAxis x:Name="YAxis" MinimumValue="0" Interval="0.4" Label="{}{}" FontSize="8" MaximumValue="1.7" MajorStroke="#FF2C2C2C" Foreground="White" BorderBrush="White" FontWeight="Bold"&gt;
                  &lt;ig:NumericYAxis.LabelSettings&gt;
                      &lt;ig:AxisLabelSettings Extent="23" Foreground="White"/&gt;
                  &lt;/ig:NumericYAxis.LabelSettings&gt;
              &lt;/ig:NumericYAxis&gt;
              &lt;ig:CategoryXAxis x:Name="XAxis" 
                                ItemsSource="{Binding}" 
                                Label="{}{IndexNum}" 
                                Interval="1" 
                                MajorStroke="Black" 
                                Foreground="White" 
                                BorderBrush="White"
                                DataContextChanged="CollectionChanged"&gt;
                  &lt;ig:CategoryXAxis.LabelSettings&gt;
                      &lt;ig:AxisLabelSettings Extent="17" VerticalAlignment="Bottom" FontSize="11" Foreground="White"/&gt;
                  &lt;/ig:CategoryXAxis.LabelSettings&gt;
              &lt;/ig:CategoryXAxis&gt;
          &lt;/ig:XamDataChart.Axes&gt;
          &lt;ig:XamDataChart.Series&gt;
  
              &lt;ig:ColumnSeries Style="{StaticResource ColumnSeriesStyle}" x:Name="Series1" ValueMemberPath="StationNumber "  XAxis="{Binding ElementName=XAxis}"  YAxis="{Binding ElementName=YAxis}" Brush="DodgerBlue" Outline="Black"&gt;
  
              &lt;/ig:ColumnSeries&gt;
          &lt;/ig:XamDataChart.Series&gt;
      &lt;/ig:XamDataChart&gt;
  </code></pre>
  
  <p>Code Behind</p>
  
  <pre><code>XAxis.ItemsSource = GeoLocations.locations;
  Series1.ItemsSource = GeoLocations.locations;
  </code></pre>