Gewusst wie: Auslösen des ScrollChanged-Ereignisses
Aktualisiert: November 2007
Beispiel
In diesem Beispiel wird dargestellt, wie das ScrollChanged-Ereignis eines ScrollViewer ausgelöst wird.
Ein FlowDocument-Element mit vier Absätzen wie in Extensible Application Markup Language (XAML) definiert. Das FlowDocument befindet sich innerhalb eines übergeordneten ScrollViewer, der sicherstellt, dass eine vertikale Bildlaufleiste sichtbar ist. Wenn das ScrollChanged-Ereignis eintritt, wird eine in C# festgelegte benutzerdefinierte Methode ausgelöst, und der Text wird in einen TextBlock geschrieben, der angibt, das das Ereignis eingetreten ist.
Der folgende Beispielcode wurde verkürzt. Das vollständige Beispiel finden Sie unter ScrollChanged-Ereignisbeispiel.
<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>
Das ScrollChanged-Ereignis wird in einer C#-Code-Behind-Datei behandelt. Wenn das ScrollChanged-Ereignis eintritt, wird eine Meldung in einer MessageBox angezeigt, die den Benutzer darauf hinweist.
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
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 = "";
}