ios 'NSUnknownKeyException'，原因：'[<ViewController 0x8a45930> setValue:forUndefinedKey:]:

'NSUnknownKeyException', reason: '[<ViewController 0x8a45930> setValue:forUndefinedKey:]:

提问by Akash kumar

I am getting this error when I run my first "sqlite" app on iPhone simulator. xcode says no issue but when i am clicking on my app it throws error in debug window. i have placed all necessary code here please help me to connect "sqlite" and remove these errors.

当我在 iPhone 模拟器上运行我的第一个“sqlite”应用程序时出现此错误。xcode 说没问题，但是当我单击我的应用程序时，它会在调试窗口中引发错误。我已经在这里放置了所有必要的代码，请帮助我连接“sqlite”并删除这些错误。

The error is as follows:

错误如下：

Terminating app due to uncaught exception 'NSUnknownKeyException', reason: '[<ViewController 0x8a45930> setValue:forUndefinedKey:]: this class is not key value coding-compliant for the key departmentbox.'
*** First throw call stack:
(0x2091012 0x119ee7e 0x2119fb1 0xc4b711 0xbccec8 0xbcc9b7 0xbf7428 0x3030cc 0x11b2663 0x208c45a 0x301bcf 0x1c6e37 0x1c7418 0x1c7648 0x1c7882 0x116a25 0x116dbf 0x116f55 0x11ff67 0xe3fcc 0xe4fab 0xf6315 0xf724b 0xe8cf8 0x1fecdf9 0x1fecad0 0x2006bf5 0x2006962 0x2037bb6 0x2036f44 0x2036e1b 0xe47da 0xe665c 0x233d 0x2265)
libc++abi.dylib: terminate called throwing an exception
(lldb) 

DBManager.m:

DBManager.m:

//
//  DBManager.m
//  sqlite
//
//  Created by Techinfiniti on 14/05/14.
//  Copyright (c) 2014 Techinfiniti. All rights reserved.
//

#import "DBManager.h"
#import <sqlite3.h>

static DBManager *sharedInstance = nil;
static sqlite3 *database = nil;
static sqlite3_stmt *statement = nil;



@implementation DBManager

+(DBManager*)getSharedInstance{

    if(!sharedInstance){
        sharedInstance = [[super allocWithZone:NULL]init];
        [sharedInstance createDB];
    }
    return sharedInstance;
}

-(BOOL)createDB{

    NSString *docsDir;
    NSArray *dirPaths;

        dirPaths = NSSearchPathForDirectoriesInDomains(NSDocumentationDirectory, NSUserDomainMask, YES);
    docsDir = dirPaths[0];
    databasePath = [[NSString alloc] initWithString:[docsDir stringByAppendingPathComponent:@"student.db"]];
    BOOL isSuccess = YES;
    NSFileManager *filemgr = [NSFileManager defaultManager];

    if([filemgr fileExistsAtPath:databasePath]== NO)
    {
        const char *dbpath = [databasePath UTF8String];
        if(sqlite3_open(dbpath,&database)== SQLITE_OK )
        {
            char *errMsg;
            const char *sql_stmt = "create table if not exists studentsDetail (regno integer primary key, name text, department text, year text)";

            if(sqlite3_exec(database,sql_stmt,NULL,NULL,&errMsg)!= SQLITE_OK)
            {

                isSuccess = NO;
                NSLog(@"failed to open create table");
            }
            sqlite3_close(database);
            return isSuccess;
        }
        else{
            isSuccess = NO;
            NSLog(@"Failed to open/create database");
        }
    }return isSuccess;

}

-(BOOL)saveData:(NSString*)registerNumber name:(NSString*)name
     department:(NSString *)department year:(NSString *)year;
{
    const char *dbpath = [databasePath UTF8String];
    if(sqlite3_open(dbpath,&database)== SQLITE_OK )
    {
        NSString *insertSQL = [NSString stringWithFormat:@"insert into studentDetail(regno,name,department,year)values(\"%d\",\"%@\",\"%@\",\"%@\")",[registerNumber integerValue],name,department,year];
        const char *insert_stmt = [insertSQL UTF8String]; sqlite3_prepare_v2(database, insert_stmt,-1,&statement,NULL);



    if(sqlite3_step(statement) == SQLITE_DONE)
{
    return YES;
}
else{
    return NO;
}
sqlite3_reset(statement);
}
return NO;

}

-(NSArray*) findByRegisterNumber:(NSString *)registerNumber
{

    const char *dbpath = [databasePath UTF8String];
    if(sqlite3_open(dbpath,&database)== SQLITE_OK)
    {
        NSString *querySQL = [NSString stringWithFormat:@"select name, department,year from studentDetail where regno=\"%@\"",registerNumber];

        const char *query_stmt = [querySQL UTF8String];
        NSMutableArray *resultArray = [[NSMutableArray alloc]init];
        if(sqlite3_prepare_v2(database,query_stmt,-1,&statement,NULL)== SQLITE_OK)
        {
            if(sqlite3_step(statement) == SQLITE_ROW)
            {
                NSString *name = [[NSString alloc] initWithUTF8String:(const char *) sqlite3_column_text(statement, 0)];
                [resultArray addObject:name];

                NSString *department = [[NSString alloc]initWithUTF8String:(const char*) sqlite3_column_text(statement,1)];
                [resultArray addObject:department];
                return resultArray;

                 NSString *year = [[NSString alloc]initWithUTF8String:(const char*) sqlite3_column_text(statement,2)];
                [resultArray addObject:year];
                return resultArray;


            }
            else{
                NSLog(@"Not Found");
                return nil;
            }
            sqlite3_reset(statement);
        }

    }
    return nil;
}

@end

ViewController.h:

视图控制器.h：

//
//  ViewController.h
//  sqlite
//
//  Created by Techinfiniti on 14/05/14.
//  Copyright (c) 2014 Techinfiniti. All rights reserved.
//

#import <UIKit/UIKit.h>
#import "DBManager.h"

@interface ViewController : UIViewController<UITextFieldDelegate>
{
    IBOutlet UITextField *regNoTextField;
    IBOutlet UITextField *nameTextField;
    IBOutlet UITextField *departmentTextField;
    IBOutlet UITextField *yearTextField;
    IBOutlet UITextField *findByRegisterNumberTextField;
    IBOutlet UIScrollView *myScrollView;
}

-(IBAction)saveData:(id)sender;
-(IBAction)findData:(id)sender;


/*
- (IBAction)find:(id)sender;

- (IBAction)save:(id)sender;


@property (weak, nonatomic) IBOutlet UITextField *findbox;

@property (weak, nonatomic) IBOutlet UITextField *regnobox;

@property (weak, nonatomic) IBOutlet UITextField *namebox;

@property (weak, nonatomic) IBOutlet UITextField *departmentbox;

@property (weak, nonatomic) IBOutlet UITextField *year;
*/

@end

ViewController.m:

视图控制器.m：

//
//  ViewController.m
//  sqlite
//
//  Created by Techinfiniti on 14/05/14.
//  Copyright (c) 2014 Techinfiniti. All rights reserved.
//

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{

    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];

    if(self)
    {


    }
    return self;
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
- (IBAction)find:(id)sender {
}

- (IBAction)save:(id)sender {
}

 */

-(IBAction)saveData:(id)sender{
    BOOL success = NO;
    NSString *alertString = @"Data Insertion falied";
    if(regNoTextField.text.length>0 && yearTextField.text.length>0 && departmentTextField.text.length>0 && yearTextField.text.length>0)
    {

        success = [[DBManager getSharedInstance]saveData:regNoTextField.text name:nameTextField.text department:departmentTextField.text year:yearTextField.text];
    }
    else
    {
        alertString = @"Enter all fields";
    }

    if(success == NO)
    {

        UIAlertView *alert = [[UIAlertView alloc]initWithTitle:alertString message:nil delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
        [alert show];
    }

}

-(IBAction)findData:(id)sender{

    NSArray *data = [[DBManager getSharedInstance]findByRegisterNumber:findByRegisterNumberTextField.text];

    if(data == nil)
    {

        UIAlertView *alert = [[UIAlertView alloc]initWithTitle:
                              @"Data Not Found" message:nil delegate:nil cancelButtonTitle:@"OK" otherButtonTitles:nil];
        [alert show];
        regNoTextField.text = @"";
        nameTextField.text = @"";
        departmentTextField.text = @"";
        yearTextField.text = @"";

    }
    else{

        regNoTextField.text = findByRegisterNumberTextField.text;
        nameTextField.text = [data objectAtIndex:0];
        departmentTextField.text = [data objectAtIndex:1];
        yearTextField.text = [data objectAtIndex:2];
    }


}


#pragma mark - Text field delegate

-(void)textFieldDidBeginEditing:(UITextField *)textField{

    [myScrollView setFrame:CGRectMake(10,50,300,200)];

}

-(BOOL) textFieldShouldReturn:(UITextField *)textField
{

    [textField resignFirstResponder];
    return YES;
}
@end

回答by Anbu.Karthik

you unused the property departmentboxinto departmentTextFieldon your ViewControllerbut you didn't to remove the departmentboxfrom storyboard,

您未使用的属性departmentbox到departmentTextField你的ViewController，但你没有删除departmentbox从故事板，

go to your connection inspector and remove the unused key department box, and then build your app

转到您的连接检查器并删除未使用的密钥department box，然后构建您的应用程序

here the department boxis shown in the Reference Outletjust removed the department boxand build your app

此处department box显示在Reference Outlet刚刚删除department box并构建您的应用程序中

回答by Vijay-Apple-Dev.blogspot.com

You have connected the UITextField in IB with "departmentbox".

您已将 IB 中的 UITextField 与“部门框”连接起来。

@property (weak, nonatomic) IBOutlet UITextField *departmentbox;

But later you have commented the above lines in your view controller.

但是后来您在视图控制器中注释了上述行。

When you try to run the app,IB is looking for the "departmentbox" in viewcontroller. That causes the crash.

当您尝试运行该应用程序时，IB 正在寻找视图控制器中的“部门框”。这导致崩溃。

disconnect the "departmentbox" in IB will resolve the issue.

断开IB中的“部门框”将解决该问题。

回答by Sash Zats

that's because you renamed you property departmentboxinto departmentTextFieldon ViewControllerbut apparently forgot to update storyboard

那是因为您将属性重命名departmentbox为departmentTextFieldonViewController但显然忘记更新故事板

Besides, there is no need to use ivars, declare private properties if you don't need to expose your outlets in .hfile:

此外，如果您不需要在.h文件中公开您的网点，则无需使用 ivars，声明私有属性：

in your .mdeclare

在你的.m声明中

@interface UIViewController ()
@property (nonatomic, weak) IBOutlet UITextField *regNoTextField;
// etc
@end

回答by Martin

This error often comes when an unknown property is associated in your xib file.

当您的 xib 文件中关联了未知属性时，通常会出现此错误。

It may happen if you rename a property after the xib association.

如果您在 xib 关联之后重命名属性，则可能会发生这种情况。

Here, the associated property was departmentbox, but renamed as departmentTextField

在这里，关联的属性是departmentbox，但重命名为DepartmentTextField

回答by mithlesh jha

Perhaps you had declared an iVar named "departmentbox" in your view controller, created a connection in xib file to that iVar and later on you deleted/renamed this iVar but forgot to delete the connection created in xib file. Can you check the xib file of your view controller class and see if there is any connection to departmentBox. If you see that (with a little warning icon showing on the right of outlet connection in xib), just remove that connection and it should be fine.

也许你已经在你的视图控制器中声明了一个名为“departmentbox”的 iVar，在 xib 文件中创建了一个到该 iVar 的连接，后来你删除/重命名了这个 iVar 但忘记删除在 xib 文件中创建的连接。你能检查一下你的视图控制器类的 xib 文件，看看是否有与 DepartmentBox 的任何连接。如果您看到（在xib 中的插座连接右侧显示一个小警告图标），只需删除该连接，它应该没问题。