public int ActiveRowIndex {get;}

{
  // get the active row index
  int rowIndex = tableView.ActiveRowIndex;
}

{
  // get the active row index
  int rowIndex = tableView.ActiveRowIndex;

  // move to a different row
  var newIndex = 10 + rowIndex;
  tableView.BringIntoView(newIndex);
}

{
  // get the active row index
  int rowIndex = tableView.ActiveRowIndex;
  // increase
  int newIndex = rowIndex + 10;
  // get the objectID
  long newOID = tableView.GetObjectIdAsync(newIndex).Result;

  // get the rowIndex for a specific objectID
  //   2nd parameter indicates if the search only occurs for the pages loaded
  //   if pass false, then in the worst case, a full table scan will occur to 
  //    find the objectID.
  long OID = 100;
  var idx = tableView.GetRowIndexAsync(OID, true);
}