アクティブな選択の書式の設定または取得 (XamSpreadsheet)

namespace IGSpreadsheet.Converters
{
    public class ExcelBoolConverter : IValueConverter
    {
        public object Convert(object value, Type targetType, object parameter,
          System.Globalization.CultureInfo culture)
        {
            if (value is ExcelDefaultableBoolean)
            {
                switch ((ExcelDefaultableBoolean)value)
                {
                    case ExcelDefaultableBoolean.True: return true;
                    case ExcelDefaultableBoolean.False: return false;
                }
            }
            return null;
        }
        public object ConvertBack(object value, Type targetType, object parameter,
          System.Globalization.CultureInfo culture)
        {
            if (value is bool)
            {
                if (targetType == typeof (ExcelDefaultableBoolean))
                {
                    return (bool)value ? ExcelDefaultableBoolean.True : ExcelDefaultableBoolean.False;
                }
            }
            return null;
        }
    }
}

Namespace IGSpreadsheet.Converters
        Public Class ExcelBoolConverter
                Implements IValueConverter
                Public Function Convert(value As Object, targetType As Type, parameter As Object, culture As System.Globalization.CultureInfo) As Object
                        If TypeOf value Is ExcelDefaultableBoolean Then
                                Select Case DirectCast(value, ExcelDefaultableBoolean)
                                        Case ExcelDefaultableBoolean.[True]
                                                Return True
                                        Case ExcelDefaultableBoolean.[False]
                                                Return False
                                End Select
                        End If
                        Return Nothing
                End Function
                Public Function ConvertBack(value As Object, targetType As Type, parameter As Object, culture As System.Globalization.CultureInfo) As Object
                        If TypeOf value Is Boolean Then
                                If targetType = GetType(ExcelDefaultableBoolean) Then
                                        Return If(CBool(value), ExcelDefaultableBoolean.[True], ExcelDefaultableBoolean.[False])
                                End If
                        End If
                        Return Nothing
                End Function
        End Class
End Namespace

<Page
  …
 xmlns:conv="clr-namspace:IGSpreadsheet.Converters"
  …>
<Page.Resources>
  <ResourceDictionary>
    <conv:ExcelBoolConverter x:Key="ExBoolConv" />
  </ResourceDictionary>
</Page.Resources>
…
<ToggleButton Content="Bold"
  IsChecked="{Binding ElementName=xamSpreadsheet1, Path=ActiveSelectionCellRangeFormat.Font.Bold,
    Converter={StaticResource ExBoolConv}}" />
…
</Page>