Width and Height values in markup

What are the values the Width of an element can take? So far I know
that you can write a number, Auto or *. Anything else?

I have the following code, I don't know how to tell the last element to
fill up the space:

<StackPanel Orientation="Horizontal">
<Separator Width="20" Margin="5,5,5,5" />
<TextBlock Text="Device Setup" />
<Separator Width="Auto" Margin="5,5,5,5" /> --> this one needs to
fill the space left
</StackPanel>

If I put Auto (like in the code above), it shrinks to zero and it
doesn't show up. If I put a number, it shows up, but fixed width. If I
put *, it crashes. Is there anything like Fill or something?

The * can only be used in the context of a grid to specify that the
remainder of the space MUST be taken by the column or row...

All other column/rows will take their "desired" height/width...

It seems that the StackPanel makes the Separator take the "minimum"
amount of space...

What you could do is embed a grid inside your stackpanel and place the
separators and textblock accordingly... as shown here:

<StackPanel>
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>

<Separator Width="20"
Margin="5,5,5,5"
Grid.Column="0"
/>
<TextBlock Text="Device Setup"
Grid.Column="1"
/>
<Separator Width="Auto"
Margin="5,5,5,5"
Grid.Column="2"
/>
</Grid>
</StackPanel >

Marcus

Or just use a DockPanel. By default the last child fills the remaining area
(LastChildFill="True").

- Doug