ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Desktop.Layouts Namespace / LayoutView Class / Extent Property
Example Version

Extent Property (LayoutView)
Gets the current extent of the layout view.
Syntax
public Envelope Extent {get;}
Example
LayoutView_ZoomTo_Extent
//Set the page extent for a layout view.

//Process on worker thread
await QueuedTask.Run(() =>
{ 
  var lytExt = layoutView.Extent;
  layoutView.ZoomTo(lytExt);
});
Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also