How to: Handle the ScrollChanged Event

Example

This example shows how to handle the ScrollChanged event of a ScrollViewer.

A FlowDocument element with Paragraph parts is defined in XAML. When the ScrollChanged event occurs due to user interaction, a handler is invoked, and text is written to a TextBlock indicating that the event has occurred.

<ScrollViewer Name="sv1" CanContentScroll="False" ScrollChanged="sChanged">

  <FlowDocument FontFamily="Arial" PageWidth="400">
    <Paragraph>
      Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut
      laoreet dolore magna aliquam erat volutpat.  Ut wisi enim ad minim veniam, quis nostrud exerci tation
      ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure.
      Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut
      laoreet dolore magna aliquam erat volutpat.  Ut wisi enim ad minim veniam, quis nostrud exerci tation
      ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure.
      Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut
      laoreet dolore magna aliquam erat volutpat.  Ut wisi enim ad minim veniam, quis nostrud exerci tation
      ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure.
    </Paragraph>
    <Paragraph>
      Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut
      laoreet dolore magna aliquam erat volutpat.  Ut wisi enim ad minim veniam, quis nostrud exerci tation
      ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure.
      Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut
      laoreet dolore magna aliquam erat volutpat.  Ut wisi enim ad minim veniam, quis nostrud exerci tation
      ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure.
      Lorem ipsum dolor sit amet, consectetuer adipiscing elit, sed diam nonummy nibh euismod tincidunt ut
      laoreet dolore magna aliquam erat volutpat.  Ut wisi enim ad minim veniam, quis nostrud exerci tation
      ullamcorper suscipit lobortis nisl ut aliquip ex ea commodo consequat. Duis autem vel eum iriure.
    </Paragraph>

  </FlowDocument>
</ScrollViewer>
private void sChanged(object sender, ScrollChangedEventArgs e)
{
    if (sv1.CanContentScroll == true)
    {
        tBlock1.Foreground = System.Windows.Media.Brushes.Red;
        tBlock1.Text = "ScrollChangedEvent just Occurred";
        tBlock2.Text = "ExtentHeight is now " + e.ExtentHeight.ToString();
        tBlock3.Text = "ExtentWidth is now " + e.ExtentWidth.ToString();
        tBlock4.Text = "ExtentHeightChange was " + e.ExtentHeightChange.ToString();
        tBlock5.Text = "ExtentWidthChange was " + e.ExtentWidthChange.ToString();
        tBlock6.Text = "HorizontalOffset is now " + e.HorizontalOffset.ToString();
        tBlock7.Text = "VerticalOffset is now " + e.VerticalOffset.ToString();
        tBlock8.Text = "HorizontalChange was " + e.HorizontalChange.ToString();
        tBlock9.Text = "VerticalChange was " + e.VerticalChange.ToString();
        tBlock10.Text = "ViewportHeight is now " + e.ViewportHeight.ToString();
        tBlock11.Text = "ViewportWidth is now " + e.ViewportWidth.ToString();
        tBlock12.Text = "ViewportHeightChange was " + e.ViewportHeightChange.ToString();
        tBlock13.Text = "ViewportWidthChange was " + e.ViewportWidthChange.ToString();
    }
    else
    {
        tBlock1.Text = "";
    }
Private Sub sChanged(ByVal sender As Object, ByVal args As ScrollChangedEventArgs)


    If (sv1.CanContentScroll = True) Then
        tBlock1.Foreground = System.Windows.Media.Brushes.Red
        tBlock1.Text = "ScrollChangedEvent just Occurred"
        tBlock3.Text = "ExtentWidth is now " + args.ExtentWidth.ToString()
        tBlock4.Text = "ExtentHeightChange was " + args.ExtentHeightChange.ToString()
        tBlock5.Text = "ExtentWidthChange was " + args.ExtentWidthChange.ToString()
        tBlock6.Text = "HorizontalOffset is now " + args.HorizontalOffset.ToString()
        tBlock7.Text = "VerticalOffset is now " + args.VerticalOffset.ToString()
        tBlock8.Text = "HorizontalChange was " + args.HorizontalChange.ToString()
        tBlock9.Text = "VerticalChange was " + args.VerticalChange.ToString()
        tBlock10.Text = "ViewportHeight is now " + args.ViewportHeight.ToString()
        tBlock11.Text = "ViewportWidth is now " + args.ViewportWidth.ToString()
        tBlock12.Text = "ViewportHeightChange was " + args.ViewportHeightChange.ToString()
        tBlock13.Text = "ViewportWidthChange was " + args.ViewportWidthChange.ToString()

    Else
        tBlock1.Text = ""

    End If

See Also

ScrollViewer
ScrollChanged
ScrollChangedEventHandler
ScrollChangedEventArgs