Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Obrat setSuma:]: unrecognized selector sent to instance 0x64139d0'

Hello how can I solve or wh开发者_高级运维at is the reason for sending me this error

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[Obrat setSuma:]: unrecognized selector sent to instance 0x64139d0'

It throw me for this line:

objectObrat.suma = [[NSString alloc] initWithString:string];

Obrat.h is :

#import <CoreData/CoreData.h>


@interface Obrat :  NSManagedObject  
{
}

@property (nonatomic, retain) NSString * cConstanatSymb;
@property (nonatomic, retain) NSString * constanatSymbol;
@property (nonatomic, retain) NSString * specSymbol;
@property (nonatomic, retain) NSString * currency;
@property (nonatomic, retain) NSString * balance;
@property (nonatomic, retain) NSString * message1;
@property (nonatomic, retain) NSString * type;
@property (nonatomic, retain) NSString * maturityDate;
@property (nonatomic, retain) NSNumber * id;
@property (nonatomic, retain) NSString * suma;
@property (nonatomic, retain) NSString * variableSymbol;
@property (nonatomic, retain) NSString * counterName;
@property (nonatomic, retain) NSString * storno;
@property (nonatomic, retain) NSString * message2;
@property (nonatomic, retain) NSString * note;
@property (nonatomic, retain) NSString * counterBank;
@property (nonatomic, retain) NSString * coounterAccount;
@property (nonatomic, retain) NSString * counterPrefix;
@property (nonatomic, retain) NSString * rate;
@property (nonatomic, retain) NSString * transactionDate;
@property (nonatomic, retain) NSDate * dateOfObrat;

@end

obrat.m is:

#import "Obrat.h"


@implementation Obrat 

@dynamic cConstanatSymb;
@dynamic constanatSymbol;
@dynamic specSymbol;
@dynamic currency;
@dynamic balance;
@dynamic message1;
@dynamic type;
@dynamic maturityDate;
@dynamic id;
@dynamic suma;
@dynamic variableSymbol;
@dynamic counterName;
@dynamic storno;
@dynamic message2;
@dynamic note;
@dynamic counterBank;
@dynamic coounterAccount;
@dynamic counterPrefix;
@dynamic rate;
@dynamic transactionDate;
@dynamic dateOfObrat;

@end

Thanks

Use @synthesize suma; instead of @dynamic suma; to instruct the compiler to generate the necessary getter and setter methods. See http://cocoadevcentral.com/d/learn_objectivec/