Specifying Grid column and row definition by style in resource - wpf

Question

There is an UserControl with the following Grid:
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition/>
</Grid.RowDefinitions>
</Grid>
Now I have a Window and there are I would to write something like that:
<Window.Resources>
<Style TargetType="Grid">
<Setter Property="RowDefinitions">
<Value>
<RowDefinition Height="*"/>
<RowDefinition/>
</Value>
</Setter>
</Style>
</Window.Resources>
The key part, which doesn't compile is when I want to change Height from Auto to *. How to do this in legal way?
In general I have to cases. 1) The first row should stretch and the second should be fixed. 2) Vice versa. Maybe a different panel than Grid could be more relevant?

Answer 1

Grid.RowDefinitions and Grid.ColumnDefinitions are no dependency properties, and can't hence be set by a Style.
You may perhaps create a dependency property FirstRowHeight in your UserControl, and bind the Height of the first RowDefinition to that property. Later you may set the FirstRowHeight property in a Style.
<Grid.RowDefinitions>
<RowDefinition Height="{Binding FirstRowHeight,
RelativeSource={RelativeSource Mode=FindAncestor, AncestorType=UserControl}}"/>
<RowDefinition/>
</Grid.RowDefinitions>
The property would look like this:
public static readonly DependencyProperty FirstRowHeightProperty =
DependencyProperty.Register(
"FirstRowHeight", typeof(GridLength), typeof(YourUserControl));
public GridLength FirstRowHeight
{
get { return (GridLength)GetValue(FirstRowHeightProperty); }
set { SetValue(FirstRowHeightProperty, value); }
}
EDIT: In order to support the simple scenario you describe at the end of your question, you may also just have an IsFirstRowFixed dependency property with a property changed callback that sets the row heights in code:
<Grid.RowDefinitions>
<RowDefinition x:Name="row1" Height="*"/>
<RowDefinition x:Name="row2" Height="Auto"/>
</Grid.RowDefinitions>
The property:
public static readonly DependencyProperty IsFirstRowFixedProperty =
DependencyProperty.Register(
"IsFirstRowFixed", typeof(bool), typeof(UserControl2),
new PropertyMetadata((o, e) => ((UserControl2)o).IsFirstRowFixedChanged()));
public bool IsFirstRowFixed
{
get { return (bool)GetValue(IsFirstRowFixedProperty); }
set { SetValue(IsFirstRowFixedProperty, value); }
}
private void IsFirstRowFixedChanged()
{
if (IsFirstRowFixed)
{
row1.Height = GridLength.Auto;
row2.Height = new GridLength(1, GridUnitType.Star);
}
else
{
row1.Height = new GridLength(1, GridUnitType.Star);
row2.Height = GridLength.Auto;
}
}

Answer 2

XAML code :
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="auto"/>
<RowDefinition Height="auto"/>
</Grid.RowDefinitions>
<Grid Grid.Row="1" Style="{StaticResource HeaderHeight}"</>
<Grid Grid.Row="1" Style="{StaticResource FooterHeight}"</>
</>
Styles in Resource dictionary
<Style TargetType="Frame" x:Name="HeaderHeight">
<Setter Property="Height" Value="700"></Setter>
</Style>
<Style TargetType="Grid" x:Name="FooterHeight">
<Setter Property="Height" Value="70"></Setter>
</Style>