Make ScrollViewer with Canvas inside scrolling smoothly in code

Question

How can I make ScrollViewer scroll my Canvas smoothly in code (no xaml)? As I know for xaml it needs to set ScrollUnit to "Pixel", but I can't do it in code.

Answer 1

If what you are after is moving the scroll one pixel with each mouse wheel turn here is the way.

Register to mouse wheel preview event.

<ScrollViewer Height="350" Width="525" PreviewMouseWheel="ScrollViewer_PreviewMouseWheel">
    <Canvas Height="650" Width="510">
        <Button Name="b" Height="30" Width="525" Content="Button text"/>
    </Canvas>
</ScrollViewer>

Move the scroll by 1 pixel on each time the event fires and set it as handled.

private void ScrollViewer_PreviewMouseWheel(object sender, System.Windows.Input.MouseWheelEventArgs e)
{
    ScrollViewer scrollViewer = sender as ScrollViewer;
    double offset = scrollViewer.VerticalOffset - Math.Sign(e.Delta);
    scrollViewer.ScrollToVerticalOffset(Math.Min(Math.Max(offset, 0), scrollViewer.ExtentHeight));
    e.Handled = true;
}