ios - Error with Parse: PFObject does not have a member named 'createdAt' -

i stuck on issue. i've read parse documentation (https://parse.com/docs/ios/guide#queries-query-constraints) doesn't helps me much.

the error

when try "createdat" or "updatedat" pfobject, got following error:

['pfobject'] not have member named 'createdat'

the code

here (shortened) function:

func loadcheckindata() {      var query = pfquery(classname: "checkin")     query.orderbydescending("createdat")     query.selectkeys(["firstname","lastname","updatedat","createdat"])      query.findobjectsinbackgroundwithblock({         (objects: [anyobject]?, error: nserror?) -> void in          if error == nil {              println(objects)             //             if let object = objects as? [pfobject] {                 println("\(object.createdat)")                  <---- error here                 self.checkedpatients = array(object.generate())             }         } else {             // log details of failure             println("error: \(error!) \(error!.userinfo!)")         }      })  } 

then retrieve "firstname", "lastname" (and try retrieve "createdat") in "checkin" parse's class following code

func collectionview(cellview: uicollectionview, cellforitematindexpath indexpath: nsindexpath) -> uicollectionviewcell {      // add parse data     if let value = checkedpatients[indexpath.row]["lastname"] as? string {         cell.celllabeltwo.text = value     }     if let value = checkedpatients[indexpath.row]["firstname"] as? string {         cell.celllabel.text = value     }     if let value = checkedpatients[indexpath.row]["createdat"] as? string {         cell.cellday.text = value     }     return cell } 

and call function

override func viewdidappear(animated: bool) {     loadcheckindata() } 

in fact tried differents method "createdat" value, , can't make works. have idea (and quick explanation if possible) nice. thank !

it's because updatedat/createdat property on pfobjects, no need retrieve using key, treat property.