wpf-devexpress-dot-xpf-dot-pdfviewer-dot-pdfviewercontrol-53abec09.md
Occurs when an end-user starts to edit an interactive form field value.
Namespace : DevExpress.Xpf.PdfViewer
Assembly : DevExpress.Xpf.PdfViewer.v25.2.dll
NuGet Package : DevExpress.Wpf.PdfViewer
public event FormFieldValueChangingEventHandler FormFieldValueChanging
Public Event FormFieldValueChanging As FormFieldValueChangingEventHandler
The FormFieldValueChanging event's data class is FormFieldValueChangingEventArgs. The following properties provide information specific to this event:
| Property | Description |
|---|---|
| Cancel | Specifies a value indicating whether to cancel changing the form field value. |
| FieldName | Gets the name of the form field. |
| 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. |
| NewValue | Gets or sets a new value of the form field. |
| OldValue | Gets the form field’s previous value. |
| 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. |
See Also