public object Convert( object value, Type targetType, object parameter, System.Globalization.CultureInfo culture )
{
if( value == null ) return null;
bool returnValue;
if( Boolean.TryParse( value.ToString(), out returnValue ) )
return !returnValue;
throw new FormatException( String.Format( "The NotConverter is waiting for a boolean value, not a {0} value.", value.GetType() ) );
}