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ScrollChanged Event

Summary

Occurs when changes are detected to the scrollbars position, extent, viewport size or visibility of the control.

Syntax

C++

public event EventHandler<ImageViewerScrollChangedEventArgs> ScrollChanged

Public Event ScrollChanged As EventHandler(Of ImageViewerScrollChangedEventArgs)

public: 
event EventHandler<ImageViewerScrollChangedEventArgs^>^ ScrollChanged

Event Data

The event handler receives an argument of type ImageViewerScrollChangedEventArgs containing data related to this event. The following ImageViewerScrollChangedEventArgs properties provide information specific to this event.

Property	Description
Handled (Inherited from System.Windows.RoutedEventArgs)
HorizontalChange	Gets a value that indicates the change in horizontal offset for a ImageViewer or RasterImageViewer.
HorizontalOffset	Gets the updated horizontal offset value for a ImageViewer or RasterImageViewer.
OriginalSource (Inherited from System.Windows.RoutedEventArgs)
RoutedEvent (Inherited from System.Windows.RoutedEventArgs)
Source (Inherited from System.Windows.RoutedEventArgs)
VerticalChange	Gets a value that indicates the change in vertical offset for a ImageViewer or RasterImageViewer.
VerticalOffset	Gets the updated vertical offset value for a ImageViewer or RasterImageViewer.

Remarks

This event is raised if any action through user interaction or programmatically that cause the scrollbars position, extent, view port size or visibility of the control.

Example

Silverlight C#

Silverlight VB

Imports Leadtools.Windows.Controls 
 
Public Sub ImageViewer_ScrollChanged(ByVal viewer As ImageViewer) 
    If Not viewer.Source Is Nothing Then 
        ' Scroll to the image center 
        AddHandler viewer.ScrollChanged, AddressOf viewer_ScrollChanged 
        viewer.ScrollViewer.ScrollToHorizontalOffset(viewer.Source.Width / 2) 
        viewer.ScrollViewer.ScrollToVerticalOffset(viewer.Source.Height / 2) 
        RemoveHandler viewer.ScrollChanged, AddressOf viewer_ScrollChanged 
    End If 
End Sub 
 
Private Sub viewer_ScrollChanged(ByVal sender As Object, ByVal e As ImageViewerScrollChangedEventArgs) 
    Dim s As String = String.Format("HorizontalOffset : {0}, VerticalOffset : {1}", e.HorizontalOffset, e.VerticalOffset) 
    MessageBox.Show(s) 
End Sub

using Leadtools.Help; 
using Leadtools.Windows.Controls; 
 
public void ImageViewer_ScrollChanged(ImageViewer viewer) 
{ 
   if (viewer.Source != null) 
   { 
      // Scroll to the image center 
      viewer.ScrollChanged += new EventHandler<ImageViewerScrollChangedEventArgs>(viewer_ScrollChanged); 
      viewer.ScrollViewer.ScrollToHorizontalOffset(viewer.Source.Width / 2); 
      viewer.ScrollViewer.ScrollToVerticalOffset(viewer.Source.Height / 2); 
      viewer.ScrollChanged -= new EventHandler<ImageViewerScrollChangedEventArgs>(viewer_ScrollChanged); 
   } 
} 
 
void viewer_ScrollChanged(object sender, ImageViewerScrollChangedEventArgs e) 
{ 
   string s = string.Format("HorizontalOffset : {0}, VerticalOffset : {1}", e.HorizontalOffset, e.VerticalOffset); 
   MessageBox.Show(s); 
}

using Leadtools.Help; 
using Leadtools.Windows.Controls; 
 
public void ImageViewer_ScrollChanged(ImageViewer viewer) 
{ 
   if (viewer.Source != null) 
   { 
      // Scroll to the image center 
      viewer.ScrollChanged += new EventHandler<ImageViewerScrollChangedEventArgs>(viewer_ScrollChanged); 
      viewer.ScrollViewer.ScrollToHorizontalOffset(((BitmapSource)viewer.Source).PixelWidth/ 2); 
      viewer.ScrollViewer.ScrollToVerticalOffset(((BitmapSource)viewer.Source).PixelHeight / 2); 
      viewer.ScrollChanged -= new EventHandler<ImageViewerScrollChangedEventArgs>(viewer_ScrollChanged); 
   } 
} 
 
void viewer_ScrollChanged(object sender, ImageViewerScrollChangedEventArgs e) 
{ 
   string s = string.Format("HorizontalOffset : {0}, VerticalOffset : {1}", e.HorizontalOffset, e.VerticalOffset); 
   MessageBox.Show(s); 
}

Imports Leadtools 
Imports Leadtools.Windows.Controls 
 
Public Sub ImageViewer_ScrollChanged(ByVal viewer As ImageViewer) 
   If Not viewer.Source Is Nothing Then 
      ' Scroll to the image center 
      AddHandler viewer.ScrollChanged, AddressOf viewer_ScrollChanged 
      viewer.ScrollViewer.ScrollToHorizontalOffset((CType(viewer.Source, BitmapSource)).PixelWidth / 2) 
      viewer.ScrollViewer.ScrollToVerticalOffset((CType(viewer.Source, BitmapSource)).PixelHeight / 2) 
      RemoveHandler viewer.ScrollChanged, AddressOf viewer_ScrollChanged 
   End If 
End Sub 
 
Private Sub viewer_ScrollChanged(ByVal sender As Object, ByVal e As ImageViewerScrollChangedEventArgs) 
   Dim s As String = String.Format("HorizontalOffset : {0}, VerticalOffset : {1}", e.HorizontalOffset, e.VerticalOffset) 
   MessageBox.Show(s) 
End Sub