Set height datagrid as height of his stackpanel, for show ve

Question

Hi,

I have this GRID:

    <Grid Margin="0,0,0,0">

        <Grid.RowDefinitions>

            <RowDefinition Height="90" />

            <RowDefinition Height="*" />

        </Grid.RowDefinitions>

In 2° row I have:

        <StackPanel Margin="0,0,0,50" Grid.Row="1" Visibility="Hidden" Name="stackPanelSearchResult">

            <GroupBox>

                <GroupBox.Header>

                    <Label Style="{StaticResource LabelFieldset}" Content="{StaticResource menuLabelGroupBoxGrid}" />

                </GroupBox.Header>

                <DataGrid Name="dgPlan"......

                ......

                </DataGrid>

        </GroupBox>

    </StackPanel>

</Grid>

How can I set the height of datagrid as hegith of stackpanel for show verticarl scrollbar?

Thanks.