How to expand a Slider to fill the available space when the slider is within a StackPanel

Question

Inserting a Slider in a Grid would expand it to fill the available space, but I would prefer not use a grid for the following reason:

I've a TextBlock and a Slider in a UserControl, the slider is spring loaded and does jog / shuttle; the current value has to be displayed because the user can't rely on the neutral cursor's position, so the textblock. Implementing the **Orientation** property of this custom slider requires both components to be rotated and also their relative position to be adjusted (left/right or top/bottom), which wouldn't be easy with a grid (unless I miss something obvious) while it is with a StackPanel.

Response to Aviad's comment

Aviad, thanks, I apologize for the pain ;-) The question was in the title: How to expand a Slider to fill the available space when the slider is within a StackPanel ?

This user control:

<UserControl x:Class="XXX.Preview.SelectionView"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Height="auto" Width="auto">
    <GroupBox Header="Selected">
        <StackPanel Orientation="Horizontal">
            <TextBlock/>
            <Slider/>
        </StackPanel>
    </GroupBox>
</UserControl>

won't expand when included in a grid even in a row with a "*" width. The slider will have no length at all.

A solution is to replace the stack panel by a grid in the code below, but I don't want to use a grid, because I need to use the Orientation property of the stack panel to show both controls stacked vertically when the enclosing user control is set in the Orientation "Vertical".

Answer 1

Very simple with binding! Note that the StackPanel as HorizontalAlignment="Stretch" and a name referred to by the binding

            <StackPanel HorizontalAlignment="Stretch" VerticalAlignment="Top" Orientation="Horizontal" Name="ParentPanel">
                <Slider Minimum="1" Maximum="999999" Interval="3" Width="{Binding Path=ActualWidth, ElementName=ParentPanel}"></Slider>
            </StackPanel>

Credits to @somedust

Follow this link to a similar question and learn how to have more control over the binding by using converters.

Answer 2

You can embed the Slider inside a Grid column that has a ColumnDefinition like Witdh="*" (i.e. will distribute available space). For example, below you can find how to get TextBlock | Slider | TextBlock layout with the slider stretched to fill the available space in the middle column:

<Grid>
    <Grid.ColumnDefinitions>
        <ColumnDefinition Width="Auto"/>
        <ColumnDefinition Width="*"/>
        <ColumnDefinition Width="Auto"/>
    </Grid.ColumnDefinitions>
    <TextBlock Grid.Column="0" Text="CutOff Fraction:"/>
    <Slider  Grid.Column="1"  
             x:Name="SliderCutOffFraction"
             IsEnabled="{Binding ElementName=ChkLanczosFilter, Path=IsChecked}"
             HorizontalAlignment="Stretch"
             Margin="2" 
             Minimum="0.5"
             Maximum="5" 
             SmallChange="0.25"
             LargeChange="0.5" 
             TickPlacement="BottomRight" 
             TickFrequency="0.5"
             Value="1"            
             ValueChanged="SliderCutOffFraction_OnValueChanged"/>
    <TextBlock Grid.Column="2" Width="20"
               DockPanel.Dock="Right"
               Text="{Binding ElementName=SliderCutOffFraction, Path=Value}"
               TextAlignment="Center"/>
</Grid>