Iphone 更改第二个视图上的字符串变量会导致错误

当尝试将JSON文件中的值发送到另一个ViewController中的字符串时，我最终遇到以下错误：

2013-08-05 08:15:50.597 AHMC[11304:70b] -[UINavigationController setSessionKey:]: unrecognized selector sent to instance 0x898d3f0
2013-08-05 08:15:50.600 AHMC[11304:70b] *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[UINavigationController setSessionKey:]: unrecognized selector sent to instance 0x898d3f0'
*** First throw call stack:
(
    0   CoreFoundation                      0x0172eed4 __exceptionPreprocess + 180
    1   libobjc.A.dylib                     0x014af8b6 objc_exception_throw + 44
    2   CoreFoundation                      0x017cbb83 -[NSObject(NSObject) doesNotRecognizeSelector:] + 275
    3   CoreFoundation                      0x0171f1fb ___forwarding___ + 1019
    4   CoreFoundation                      0x0171edde _CF_forwarding_prep_0 + 14
    5   AHMC                                0x00008013 -[LoginViewController loginAction:] + 963
    6   libobjc.A.dylib                     0x014c1874 -[NSObject performSelector:withObject:withObject:] + 77
    7   UIKit                               0x0023c968 -[UIApplication sendAction:to:from:forEvent:] + 108
    8   UIKit                               0x0023c8f4 -[UIApplication sendAction:toTarget:fromSender:forEvent:] + 61
    9   UIKit                               0x00330581 -[UIControl sendAction:to:forEvent:] + 66
    10  UIKit                               0x00330944 -[UIControl _sendActionsForEvents:withEvent:] + 577
    11  UIKit                               0x0032fbf3 -[UIControl touchesEnded:withEvent:] + 641
    12  UIKit                               0x0027956d -[UIWindow _sendTouchesForEvent:] + 852
    13  UIKit                               0x0027a172 -[UIWindow sendEvent:] + 1134
    14  UIKit                               0x0024df06 -[UIApplication sendEvent:] + 242
    15  UIKit                               0x00238b0f _UIApplicationHandleEventQueue + 11421
    16  CoreFoundation                      0x016b817f __CFRUNLOOP_IS_CALLING_OUT_TO_A_SOURCE0_PERFORM_FUNCTION__ + 15
    17  CoreFoundation                      0x016b7b0b __CFRunLoopDoSources0 + 235
    18  CoreFoundation                      0x016d4bde __CFRunLoopRun + 910
    19  CoreFoundation                      0x016d4403 CFRunLoopRunSpecific + 467
    20  CoreFoundation                      0x016d421b CFRunLoopRunInMode + 123
    21  GraphicsServices                    0x03697a37 GSEventRunModal + 192
    22  GraphicsServices                    0x0369785e GSEventRun + 104
    23  UIKit                               0x0023b6bb UIApplicationMain + 1225
    24  AHMC                                0x00009d8d main + 141
    25  libdyld.dylib                       0x01d6b70d start + 1
    26  ???                                 0x00000001 0x0 + 1
)
libc++abi.dylib: terminating with uncaught exception of type NSException

下面是将变量的新值发送到下一个视图控制器上的变量的代码

FirstViewController *dash = [self.storyboard instantiateViewControllerWithIdentifier:@"dashboard"];

    dash.sessionKey = [jsonArray objectForKey:@"new_session_key"];

通过使用NSLog测试，我验证了new_session_key的值是什么，它是“262040c7c199e59abfe78009f3ecd8”

是的，我在第二个视图的头文件中创建了变量：

 @interface FirstViewController : UIViewController
{
    NSString *sessionKey;
}

@property (nonatomic, retain) NSString *sessionKey;

---

请帮助我解释为什么会出现此错误。

如果您仔细查看错误的第一行

---

-[UINavigationController setSessionKey:]：发送到实例0x898d3f0的选择器无法识别

因此，与其调用FirstViewController的sessionKey属性，不如尝试为UINavigationController调用它，而这正是导致崩溃的原因

我想请您检查FirstViewController的情节提要ID。。。我相信您正在使用UINavigationController=>“仪表板”的情节提要ID

我希望它有助于解决崩溃问题
从[jsonArray objectForKey:@“new_session_key”]获取的返回值是一个字符串？您是否在.m文件中合成了sessionKey？
-[UINavigationController setSessionKey:]：发送到实例0x898d3f0的无法识别的选择器
您是否在Interface Builder中输入了子类
FirstViewController
？您需要先进行语法化，然后才能将该属性访问到下一个视图控制器…..似乎无法合成它，它无法识别变量。我根本不明白您写了什么。。。好吧，怎么修，好的。。能否打开故事板并为FirstViewController选择viewcontroller。请检查情节提要id。复制该情节提要id，并在以下代码中将其替换为“dashboard”
FirstViewController*dash=[self.storyboard InstanceDeviceController WithiIdentifier:@“dashboard”]
并确保在第三个选项卡（Identity Inspector）的右侧（实用程序）中输入了自定义类
FirstViewController