OnPageNumberChanged event

Fired when the visible page number changes due to scrolling. The Sender parameter references the TPdfView instance that raised the event, so a single handler can serve multiple views by inspecting Sender

Typical uses include: notify a navigation control that the user is now reading a different page in continuous mode. Because the handler runs on the VCL main thread, you can update form controls and call other VCL APIs directly

Handlers must return quickly — PDFium rendering and form filling occur on the same thread, and any delay here postpones the next page repaint

• Set TabStop to True if you want this control to participate in tab-key focus traversal so that keyboard events are delivered
• When you assign this event at design-time the IDE generates a stub procedure on the form; you can also assign it at run-time with PdfView1.OnPageNumberChanged := MyHandler
• Combine with the matching Set Cursor / Set Caret calls on TPdfView to keep visual feedback synchronised