![]() | Trigger Events |
The PdfWidgetAnnotation, PdfPage, PdfDocument ,or PdfField include a property named AdditionalAction that specifies an additional-actions that extends the set of events that can trigger the execution of an action.
The AnnotationPageOpen and AnnotationPageClose trigger events in the PdfAnnotationLevelActions have a similar function to the PageOpened and PageClosed in the PdfPageLevelActions class. However, associating these triggers with annotations allows annotation objects to be self-contained and greatly simplifies authoring. For example, annotations containing such actions can be copied or moved between pages without requiring page open/close actions to be changed.
The AnnotationPageVisible and AnnotationPageInvisible trigger events allow a distinction between pages that are open and pages that are visible. At any one time, only a single page is considered open in the viewer application, while more than one page may be visible, depending on the page layout.
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For these trigger events, the values of the PdfAnnotationFlags have no bearing on whether a given trigger event occurs. |
The field-related trigger events (PdfFieldLevelActions) FieldKeystroke, FieldFormat, FieldValidate, and FieldCalculate are not defined for button fields (see PdfButtonField).