It is possible to use an existing ViewController with PerformSegueWithIdentifier?

Question

I use the method performSegueWithIdentifier:sender: to open a new ViewController from a storyboard-file programmatically. This works like a charm.

But on every time when this method is being called, a new ViewController would be created. Is it possible to use the existing ViewController, if it exista? I don't find anything about this issue (apple-doc, Stack Overflow, ...).

The Problem is: On the created ViewController the user set some form-Elements and if the ViewController would be called again, the form-elements has the initial settings :(

Any help would be appreciated.

Edit: I appreciate the many responses. Meanwhile, I'm not familiar with the project and can not check your answers.

Answer 1

Use shouldPerforSegueWithIdentifier to either allow the segue to perform or to cancel the segue and manually add your ViewController. Retain a pointer in the prepareForSegue.

... header

@property (strong, nonatomic) MyViewController *myVC;

... implementation

-(BOOL) shouldPerformSegueWithIdentifier:(NSString *)identifier sender:(id)sender{
    if([identifier isEqualToString:@"MySegueIdentifier"]){
        if(self.myVC){
            // push on the viewController
            [self.navigationController pushViewController:self.myVC animated:YES];
             // cancel segue
            return NO; 
        }
    }
    // allow the segue to perform
    return YES;
}


-(void) prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
    if([segue.identifier isEqualToString:@"MySegueIdentifier"]){
        // this will only be called the first time the segue fires for this identifier
        // retian a pointer to the view controller
        self.myVC = segue.destinationViewController;
    }
}