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Postupy: Zpracování události ScrollChanged

  • Článek

Příklad

Tento příklad ukazuje, jak zpracovat událost ScrollChanged ve ScrollViewer.

Prvek FlowDocument s částmi Paragraph je definován v jazyce XAML. Když dojde k události ScrollChanged z důvodu interakce uživatele, vyvolá se obslužná rutina a text se zapíše do TextBlock označující, že k události došlo.

<ScrollViewer Name="svrContent" 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 (svrContent.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

Viz také