How to increase scrollbar width in WPF ScrollViewer?

Solution 1:

The ScrollBar template reaches out for system parameters to determine its width/height (depending on orientation). Therefore, you can override those parameters:

<ScrollViewer>
    <ScrollViewer.Resources>
        <sys:Double x:Key="{x:Static SystemParameters.VerticalScrollBarWidthKey}">100</sys:Double>
    </ScrollViewer.Resources>
</ScrollViewer>

Solution 2:

Kent's answer can also be applied to easily all scrollbars in your application by placing it in your App.xaml resources, and by specifying the horizontal height key as well.

<Application
    xmlns:sys="clr-namespace:System;assembly=mscorlib"
    ...
>
    <Application.Resources>
        <sys:Double x:Key="{x:Static SystemParameters.VerticalScrollBarWidthKey}">50</sys:Double>
        <sys:Double x:Key="{x:Static SystemParameters.HorizontalScrollBarHeightKey}">50</sys:Double>
    </Application.Resources>
</Application>