WPF layout riddle

Question

Say I've got two elements in a window.
I'd like element A to fill all unused vertcial space and have always at least eg. 200px height.
Element B will have few fixed sizes (expander) and it should be given the space it demands (but leaving at least 200px for A). If there is not enough free space in a window, B should be scrollable.

That's close to what I wan't to achive, but DockPanel doesn't respect MinHeight property.

<DockPanel>
  <ScrollViewer DockPanel.Dock="Bottom">
    <B/>
  </ScrollViewer>
  <A MinHeight="200"/>
</DockPanel>

Is there any way to do it using WPF native panels?

Answer 1

A DockPanel will always process the panels in the order they are defined in; it won't make a docked element smaller just because the last element has a MinHeight.

I would use a Grid:

<Grid>
  <Grid.RowDefinitions>
    <RowDefinition Height="*" MinHeight="200" />
    <RowDefinition Height="Auto" />
  </Grid.RowDefinitions>
  <A Grid.Row="0"/>
  <ScrollViewer Grid.Row="1">
    <B/>
  </ScrollViewer>
</Grid>