title: Why would I get a "BoolToRowHeightConverter is not supported in a Windows Presentation Foundation(WPF) project error in xaml?
body: <p>Why would I get a "BoolToRowHeightConverter is not supported in  a Windows Presentation Foundation(WPF) project error in xaml?
  I was using a converter to convert rowheight to * and Auto in a grid based on the expander's IsExpanded property.</p>
  
  <p>Code in xaml:</p>
  
  <pre><code>     &lt;RowDefinition Height="{Binding IsExpanded, ElementName=Expander5, Converter={x:Static BoolToRowHeightConverter.Instance}}"/&gt;
  </code></pre>
  
  <p>Code in xaml.cs:</p>
  
  <pre><code>    public class BoolToRowHeightConverter : IValueConverter
      {
          public object Convert(object value, Type targetType, object   parameter, System.Globalization.CultureInfo culture)
          {
              if ((bool)value) return new GridLength(1, GridUnitType.Star);
              else
                  return GridLength.Auto;
  
          }
          public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)
          {
              throw new NotImplementedException();
          }
  
  
      }
  </code></pre>