控件自适应的问题

Question

如下代码，我需要   Button 的高度，也自动为700，该如何实现呢？
<Grid Background="White" Width="600" Height="700">
        <Grid.ColumnDefinitions>
            <ColumnDefinition />
        </Grid.ColumnDefinitions>
        <Grid.RowDefinitions >
            <RowDefinition Height="Auto" />
        </Grid.RowDefinitions>

        <Button Content="xxx" Height="auto" ></Button>

    </Grid>

Answer 1

记得好像是
<Button Content="xxx" Height="100*" ></Button>

Answer 2

已解决，SizeChanged解决。如this.SizeChanged += new SizeChangedEventHandler(SilverlightControl2_SizeChanged);


            void SilverlightControl2_SizeChanged(object sender, SizeChangedEventArgs e)
        {
            this.xxx.Height = this.ActualHeight;
        }