[NSManagedObjectContext delete:]: unrecognized selector sent to instance - ios

Question

core data getting on my nerves. i' m deleting old data and want to insert new data received from server.
now the deleting part gives a "sigabort":
-[NSManagedObjectContext delete:]: unrecognized selector sent to instance 0x522f550
2013-09-27 14:05:56.592 * Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[NSManagedObjectContext delete:]: unrecognized selector sent to instance 0x522f550'
* First throw call stack:
(0x320f82a3 0x39d4797f 0x320fbe07 0x320fa531 0x32051f68 0x1b6c53 0x1868e5 0x3a15f11f 0x3a16d259 0x3a16d3b9 0x3a193a11 0x3a1938a4)
libc++abi.dylib: terminate called throwing an exception
deleting happens in background and nsmanagedobjectcontext is a privet concurrency type
i printed the pointer for context and object context
po context NSManagedObjectContext: 0x522f550
and
po tmpCon.managedObjectContext NSManagedObjectContext: 0x522f550>
and the code for deleting is:
NSError *errorAllCons = nil;
NSFetchRequest *allevents = [[NSFetchRequest alloc] init];
[allevents setEntity:[NSEntityDescription entityForName:#"TEventContact" inManagedObjectContext:context]];
NSArray *allCons = [context executeFetchRequest:allevents error:&errorAllCons];
for (TEventContact *tmpCon in allCons)
{
[context delete:tmpCon];
}
and it crashes on [context delete:tmpCon];
can someone let me know what am i doing wrong?

Answer 1

Use
[context deleteObject:tmpCon];
It will solve the problem

Answer 2

do it like this for deleting an object permanently
for (TEventContact *tmpCon in allCons)
{
[context deleteObject:tmpCon] /// for deleting object in context
}
[context save]; /// to reflect changes in database you need to save that context
without saving the context it doesn't reflect on data base and that may cause DIRTY_READ for another context