Associating slider values ​​at thumb height in WPF

Question

I have a problem with data binding in WPF.

I would like to “adjust” the slider so that the thumb grows when you move the slider to the right, and the thumb contracts when you move the slider to the left.

So, I edited the template for the slider and changed the appearance of the slider, so the slider looks like I want it.

But now I need to bind the height of the thumb to the value of the slider, but I do not know how this works.

I made some simple data related to things, but I can’t understand how I can attach this “thumb height”, which is inside my slider template, to the value of the slider, which is inside the user control where my slider is located.

So how can I do this?

Answer 1

You can use the RelativeSource binding ( Height="{Binding Value, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Slider}}}" ).

Here's an example of a thumb style that depends on Slider.Value:

 <Style x:Key="SliderThumbStyle" TargetType="{x:Type Thumb}"> <Setter Property="SnapsToDevicePixels" Value="true"/> <Setter Property="OverridesDefaultStyle" Value="true"/> <Setter Property="Width" Value="14"/> <Setter Property="Template"> <Setter.Value> <ControlTemplate TargetType="{x:Type Thumb}"> <Ellipse Name="Ellipse" Fill="#C0C0C0" Stroke="#404040" Height="{Binding Value, RelativeSource={RelativeSource FindAncestor, AncestorType={x:Type Slider}}}" StrokeThickness="1" /> <ControlTemplate.Triggers> <Trigger Property="IsMouseOver" Value="True"> <Setter TargetName="Ellipse" Property="Fill" Value="#808080"/> </Trigger> <Trigger Property="IsEnabled" Value="false"> <Setter TargetName="Ellipse" Property="Fill" Value="#EEEEEE"/> </Trigger> </ControlTemplate.Triggers> </ControlTemplate> </Setter.Value> </Setter> </Style> 

Hope this helps.

Greetings from Anwaki

Answer 2

Check out my question and answer here -

In WPF / XAML, how do I resize a paragraph of text using a scrollbar?

If you have something like this:

 <ScrollBar x:Name="scroll1"></ScrollBar> <Image Height="{Binding ElementName=scroll1, Path=Value}" /> 

NB I am not 100% sure of the syntax for the image, so you need to accept this as pseudo code.