Problem assigning values to membervariables , objective c

i have a view controller like so

@interface Preferences1 : UIViewController<selectedtimedelegate> 
{

    NSString *Expiration;
        NSString *incomingalerts;
        NSString *destroyby;
}

in my implementation i am trying to navigate to another screen while assigning the current values to the member variables of the next viewcontroller.

-(IBAction)nextbuttonpressed:(id)sender
{

    Preferences2 *addController = [[Preferences2 alloc] initWithNibName:@"Preferences2" bundle:[NSBundle mainBundle]];  
    addController.Expiration1 = Expiration ;
    [self.navigationController pushViewController:addControl开发者_开发知识库ler animated:YES];
    [addController release];


}

in Preferences2 viewcontroller i have set the property like so

@property(nonatomic ,retain) NSString *Expiration1;

when i am on the Preferences2 screen i dont see the values, in fact the program crashes while the values are being assigned. can somebody tell me where i am going wrong.

Thanks.

---

You are missing some where like this:

Are you sure this thing is in Prefernce2,because your code shows something wrong either by typing mistake or the real one.So,check it out.

@interface Preferences1 (Over here it should be Preferences2): UIViewController {

NSString *Expiration; //You need to define this string in Prefernce2 & synthesize in .m
    NSString *incomingalerts;
    NSString *destroyby;

} @property(nonatomic ,retain) NSString *Expiration1;