ArcGIS Pro 2.6 API Reference Guide
Refresh Method (LayoutView)
Example 

ArcGIS.Desktop.Layouts Namespace > LayoutView Class : Refresh Method
Force the layout view to redraw. This method must be called on the MCT. Use QueuedTask.Run.
Syntax
public void Refresh()
Public Sub Refresh() 
Exceptions
ExceptionDescription
This method or property must be called within the lambda passed to QueuedTask.Run.
Example
//Refresh the layout view.

//Process on worker thread
await QueuedTask.Run(() => layoutView.Refresh());
Requirements

Target Platforms: Windows 10, Windows 8.1, Windows 7

See Also

Reference

LayoutView Class
LayoutView Members