ArcGIS Pro 2.6 API Reference Guide
BoundingBox Property

ArcGIS.Desktop.Core.Portal Namespace > PortalQueryParameters Class : BoundingBox Property
Gets or sets the search extent for a spatial search. A valid search requires either a bounding box, or a Query, or both.
Syntax
public Envelope BoundingBox {get; set;}
Public Property BoundingBox As Envelope
Remarks
Corresponds to the "bbox=" parameter of a portal REST query.
Spatial search is an overlaps/intersects function of the search extent and the extent of the document. Sorting in a spatial search is not supported. Documents that have no extent (e.g., mxds, 3dds, lyr) will not be found when doing a spatial search. Note: Document extent must be in geographic coordinates (wgs84).
Using an envelope not in wgs84 will result in an exception when executing the query
Requirements

Target Platforms: Windows 10, Windows 8.1, Windows 7

See Also

Reference

PortalQueryParameters Class
PortalQueryParameters Members