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

ArcGIS.Desktop.Reports Namespace > ReportView Class : SelectElements Method
A list of existing report elements. If null then all elements are unselected.
Set the selected report elements for the report view.
Syntax
public void SelectElements( 
   IReadOnlyList<Element> elements
)
Public Sub SelectElements( _
   ByVal elements As IReadOnlyList(Of Element) _
) 

Parameters

elements
A list of existing report elements. If null then all elements are unselected.
Remarks
If a child of a group element is provided in the list of elements to be selected in addition to its parent then the parent is the element selected. In addition if multiple section elements are in the list of elements, then only the first section element is selected.
Example
//ReportDetailsSection contains the "Fields"
var elements = reportDetailsSection.GetElementsAsFlattenedList();
reportDetailsSection.SelectElements(elements);
Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

ReportView Class
ReportView Members