ArcGIS Pro 2.8 API Reference Guide
ZoomToPageWidth Method (ReportView)
Example 

ArcGIS.Desktop.Reports Namespace > ReportView Class : ZoomToPageWidth Method
Zoom the report view to the width of the page. This method must be called on the MCT. Use QueuedTask.Run.
Syntax
public bool ZoomToPageWidth()
Public Function ZoomToPageWidth() As Boolean

Return Value

Returns true if the navigation is completed, false if it was interrupted by another view navigation.
Exceptions
ExceptionDescription
This method must be called within the lambda passed to QueuedTask.Run.
Example
//Process on worker thread
QueuedTask.Run(() => reportView.ZoomToPageWidth());     
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

ReportView Class
ReportView Members