未捕获的异常：此类不符合键值编码 [英] Uncaught exception: This class is not key value coding-compliant

问题描述

我正在关注一个名为适用于iOS的Swift教程：NSFileManager持久数据的教程，我在29分钟左右或之后遇到错误。当我尝试在iOS模拟器上运行它时，我收到错误：

I'm following a tutorial titled "Swift Tutorial for iOS : NSFileManager Persisting Data", and I've encountered an error around or after the 29 minute mark. When I try running it on the iOS simulator, I receive the error:

由于未捕获的异常'NSUnknownKeyException'而终止应用程序，原因：' [setValue：forUndefinedKey：]：此类与密钥theLoadMethod不符合密钥值。'

Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[ setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key theLoadMethod.'

显然基于错误，我认为问题是我的 theLoadMethod 。这是 all 我在ViewController中作为此项目的一部分编写的代码：

Obviously based off the error, I'm thinking the problem is my theLoadMethod. Here is all the code I wrote as part of this project in the ViewController:

let theDocumentsFolder = NSSearchPathForDirectoriesInDomains(.DocumentDirectory, .UserDomainMask, true)[0] as String
let theFileName     = "/theUserFile.txt"
let thePath         = theDocumentsFolder.stringByAppendingString(theFileName)


class ViewController: UIViewController {

@IBOutlet weak var nameTextField: UITextField!
@IBOutlet weak var lastNameTextField: UITextField!
@IBOutlet weak var ageTextField: UITextField!

@IBOutlet weak var theLabel: UILabel!

// The save method
@IBAction func theSaveMethod(sender: AnyObject) {
    var name        = nameTextField.text
    var lastName    = lastNameTextField.text
    var age         = ageTextField.text

    var theString   =   "The user's information is: \(name), \(lastName), \(age)"

    let theFileManager = NSFileManager.defaultManager()

    if !theFileManager.fileExistsAtPath(thePath) {

        var writeError:NSError?
        let fileToBeWritten = theString.writeToFile(thePath, atomically: true, encoding: NSUTF8StringEncoding, error: &writeError)

        if writeError == nil {
            println("No errors. Added: \(theString)")
        } else {
            println("Encountered an error. Error is: \(writeError)")
        }

    } else {
        println("File already exists")
    }

    nameTextField.resignFirstResponder()
    lastNameTextField.resignFirstResponder()
    ageTextField.resignFirstResponder()
}

@IBAction func theLoadMethod(sender: AnyObject) {
    let infoFromFile:String = String.stringWithContentsOfFile(thePath, encoding: NSUTF8StringEncoding, error: nil)!

    theLabel.text = infoFromFile
}

有没有什么我做错了？据我所知，我的所有iOS屏幕元素都被正确命名和链接。

Is there anything I'm doing wrong? As far as I'm aware, all my iOS on screen elements are correctly named and linked.

推荐答案

这通常是由故事板到不存在的属性的链接引起的。仔细检查故事板中对象的所有链接。此外，如果您更改了属性或方法的名称或拼写，它仍然可以引用旧属性或方法。

This is normally caused by a link from your storyboard to a non existent property. Double check all the links from objects in your storyboard. Also if you have changed the name or spelling of a property or method it can still have a reference to the old one.

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