<Grid x:Name="LayoutRoot">
    <Grid.RowDefinitions>
        <RowDefinition Height="*"/>
        <RowDefinition Height="*"/>
        <RowDefinition Height="*"/>
    </Grid.RowDefinitions>
    <Grid x:Name="container1" Grid.Row="0" >
        <Grid Name="grid1" Background="Aqua" Margin="15"></Grid>
    </Grid>
<Grid x:Name="container2" Grid.Row="1" >
        <Grid Name="grid2" Background="blue" Margin="15"></Grid>
    </Grid>
    <Grid x:Name="container3" Grid.Row="2" >
        <Grid Name="grid3" Background="green" Margin="15"></Grid>
    </Grid>
</Grid>