ArcGIS Pro 2.6 API Reference Guide
HasPreviousCamera Method
Example 

ArcGIS.Desktop.Mapping Namespace > MapView Class : HasPreviousCamera Method
Indicates whether the map view has a previous camera position.
Syntax
public bool HasPreviousCamera()
Public Function HasPreviousCamera() As Boolean

Return Value

Returns true if the map view has a previous camera position.
Remarks
The map view will have a previous camera position if the camera has changed before, and if the camera stack has not been rewound to the beginning.
Example
Zoom to the previous camera position.
public Task<bool> ZoomToPreviousCameraAsync()
{
  //Get the active map view.
  var mapView = MapView.Active;
  if (mapView == null)
    return Task.FromResult(false);

  //Zoom to the selected layers in the TOC
  if (mapView.HasPreviousCamera())
    return mapView.PreviousCameraAsync();

  return Task.FromResult(false);
}
Requirements

Target Platforms: Windows 10, Windows 8.1, Windows 7

See Also

Reference

MapView Class
MapView Members