我有一个我从Parse为PFUser构建的模型:
import Foundation
import Parse
class TradeUser : PFUser {
override class func initialize() {
self.registerSubclass()
}
var userID : String {
get {return objectForKey("objectId") as! String}
set { setObject(newValue, forKey: "objectId") }
}
var emailAddress : String {
get {return objectForKey("email") as! String}
set { setObject(newValue, forKey: "email") }
}
var firstName : String {
get {return objectForKey("firstName") as! String}
set {setObject(newValue, forKey: "firstName")}
}
var lastName : String {
get {return objectForKey("lastName") as! String}
set {setObject(newValue, forKey: "lastName")}
}
var primaryQueue : String {
get {return objectForKey("primaryQueue") as! String}
set {setObject(newValue, forKey: "primaryQueue")}
}
var image : PFFile {
get { return self["profileImage"] as! PFFile }
set { self["profileImage"] = newValue }
}
}
但是当我查询获取用户并尝试将其投射时,我得到了一个"无法投射类型' PFUser' (0x107555928)到' ShiftSwap.TradeUser' (0x10754e910)"
我认为TradeUser与PFUser的价值类型相同,因为它是PFUser演员?我有点困惑,任何澄清都会受到赞赏!
修改:
@IBAction func chatBarButton(sender: AnyObject) {
let postingUser = self.object?.objectForKey("userID") as! String
let tradeUserQuery = PFUser.query()
tradeUserQuery?.whereKey("objectId", equalTo: postingUser)
let trader = tradeUserQuery?.getFirstObject() as! TradeUser
var chatVC = MessagesViewController()
chatVC.currentUser = TradeUser.currentUser()
print(TradeUser.currentUser())
chatVC.otherUser = trader
self.navigationController?.pushViewController(chatVC, animated: true)
}
答案 0 :(得分:0)
你正在逼迫这是不可能的。您不能将基类PFUser的实例向下转换为派生的一个TradeUser。