windows8中的Slider数据绑定问题

 

<Grid Background="{StaticResource ApplicationPageBackgroundThemeBrush}">
  <Slider HorizontalAlignment="left" Margin="460,182,0,0" VerticalAlignment="Top" Width="469" Height="36" Maximum="100" Minimum="0"/>
  <TextBox Margin="536,77,0,0" Height="42" Width="237" Text="{Binding value,ElementName=slider1,Mode=TwoWay}">
</Grid>