PdfViewerControl.AnnotationChanging Event

Fires before an annotation is changed.

Namespace: DevExpress.Xpf.PdfViewer

Assembly: DevExpress.Xpf.PdfViewer.v21.2.dll

NuGet Package: DevExpress.Wpf.PdfViewer

Declaration

C#

public event PdfAnnotationChangingEventHandler AnnotationChanging

VB.NET

Public Event AnnotationChanging As PdfAnnotationChangingEventHandler

Event Data

The AnnotationChanging event's data class is PdfAnnotationChangingEventArgs. The following properties provide information specific to this event:

Property	Description
Cancel	Gets or sets whether the event should be canceled.
Handled	Gets or sets a value that indicates the present state of the event handling for a routed event as it travels the route. Inherited from RoutedEventArgs.
NewAnnotation	Returns an annotation’s new property values.
OldAnnotation	Returns an annotation’s previous property values.
OriginalSource	Gets the original reporting source as determined by pure hit testing, before any possible Source adjustment by a parent class. Inherited from RoutedEventArgs.
RoutedEvent	Gets or sets the RoutedEvent associated with this RoutedEventArgs instance. Inherited from RoutedEventArgs.
Source	Gets or sets a reference to the object that raised the event. Inherited from RoutedEventArgs.

The event data class exposes the following methods:

Method	Description
InvokeEventHandler(Delegate, Object)	When overridden in a derived class, provides a way to invoke event handlers in a type-specific way, which can increase efficiency over the base implementation. Inherited from RoutedEventArgs.
OnSetSource(Object)	When overridden in a derived class, provides a notification callback entry point whenever the value of the Source property of an instance changes. Inherited from RoutedEventArgs.

Remarks

The code sample below prohibits changing annotations of a specific author:

XAML

<dxpdf:PdfViewerControl x:Name="pdfViewer" 
                        AnnotationChanging="pdfViewer_AnnotationChanging">

C#

private void pdfViewer_AnnotationChanging(object sender, PdfAnnotationChangingEventArgs e)
{
    if (e.OldAnnotation.Author == "Cardle Anita L") { e.Cancel = true; }
}

VB.NET

Private Sub pdfViewer_AnnotationChanging(ByVal sender As Object, ByVal e As PdfAnnotationChangingEventArgs)
  If e.OldAnnotation.Author = "Cardle Anita L" Then
    e.Cancel = True
  End If
End Sub