ScrollChangedEventHandler Delegate
Represents the method that will handle the ScrollViewer.ScrollChanged routed event.
Assembly: PresentationFramework (in PresentationFramework.dll)
'Declaration Public Delegate Sub ScrollChangedEventHandler ( _ sender As Object, _ e As ScrollChangedEventArgs _ ) 'Usage Dim instance As New ScrollChangedEventHandler(AddressOf HandlerMethod)
In XAML, you can use delegates but you cannot define your own.
Parameters
- sender
- Type: System.Object
The object where the event handler is attached.
- e
- Type: System.Windows.Controls.ScrollChangedEventArgs
The event data.
This example shows how to raise the ScrollChanged event of a ScrollViewer.
A FlowDocument element with four Paragraphs as defined in Extensible Application Markup Language (XAML). The FlowDocument resides within a parent ScrollViewer, which ensures that a vertical scroll bar will be visible. When the ScrollChanged event occurs, a custom method defined in C# is raised, and text is written to a TextBlock indicating that the event has occurred.
The following sample code is abbreviated. For the complete sample, see ScrollChanged Event Sample.
<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>
The ScrollChanged event is handled in a C# code-behind file. When the ScrollChanged event occurs, a MessageBox displays a message indicating that to the user.
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
Windows 7, Windows Vista, Windows XP SP2, Windows Server 2008 R2, Windows Server 2008, Windows Server 2003
The .NET Framework and .NET Compact Framework do not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.