How can i bind parent's property to its child's property? - silverlight

Question

I have a GroupBox, which is defined like this
<ResourceDictionary
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:Groupbox"
>
<Style TargetType="local:GroupBox">
<Setter Property="BorderBrush" Value="DarkGray"/>
<Setter Property="BorderThickness" Value="1"/>
<Setter Property="Padding" Value="6"/>
<Setter Property="Template">
<Setter.Value>
<ControlTemplate TargetType="local:GroupBox">
<Grid Background="{TemplateBinding Background}">
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Border BorderThickness="{TemplateBinding BorderThickness}" Grid.Row="1" Grid.RowSpan="2" BorderBrush="{TemplateBinding BorderBrush}" CornerRadius="3">
<Border.Clip>
<GeometryGroup FillRule="EvenOdd">
<RectangleGeometry x:Name="FullRect" Rect="0,0,300,200"/>
<RectangleGeometry x:Name="HeaderRect" Rect="6,0,100,100"/>
</GeometryGroup>
</Border.Clip>
</Border>
<ContentPresenter Grid.Row="2" ContentTemplate="{TemplateBinding ContentTemplate}" Content="{TemplateBinding Content}" Margin="{TemplateBinding Padding}"/>
<ContentControl x:Name="HeaderContainer" Margin="6,0,0,0" Grid.Row="0" Grid.RowSpan="2" HorizontalAlignment="Left">
<ContentPresenter Margin="3,0,3,0" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}"/>
</ContentControl>
</Grid>
</ControlTemplate>
</Setter.Value>
</Setter>
</Style>
</ResourceDictionary>
And i'm using this control like this
<Controls:GroupBox x:Name="GroupBox">
<Controls:GroupBox.HeaderTemplate>
<DataTemplate>
<CheckBox "Header" x:Name="cbHeader"/>
</DataTemplate>
</Controls:GroupBox.HeaderTemplate>
<Controls:GroupBox>
So, well, my questions - how can i bind property IsEnabled of GroupBox to the Checkbox property IsChecked?
Thanks in advance.

Answer 1

Didn't try it but you should be able to do something like this:
<Controls:GroupBox x:Name="MyGroupBox">
<Controls:GroupBox.HeaderTemplate>
<DataTemplate>
<CheckBox IsChecked="{Binding Path=IsEnabled, ElementName=MyGroupBox, Mode=TwoWay}" Content="Header" x:Name="cbHeader" />
</DataTemplate>
</Controls:GroupBox.HeaderTemplate>
<Controls:GroupBox>

Answer 2

In fact there was no need to define DataTemplate. This code works the same way.
<Panels:GroupBox>
<Panels:GroupBox.Header>
<CheckBox Content="Header" x:Name="cbHeader" IsChecked="{Binding IsHeaderChecked}" />
</Panels:GroupBox.Header>
<ContentControl HorizontalContentAlignment="Stretch" VerticalContentAlignment="Stretch" IsEnabled="{Binding Path=IsChecked, ElementName=cbHeader}"/>
</Panels:GroupBox>