调用presentModalViewController后要卸载视图吗？

myViewController *myView = [[myViewController alloc] initWithNibName:nil bundle:nil];
    myView.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
    [self presentModalViewController:myView animated:YES];
    [myView release];

//This would be in an action or something...
if (self.myViewControllerProperty == nil) {
    self.myViewControllerProperty = [[[MyViewController alloc] initWithNibName:nil bundle:nil] autorelease];
}

[self presentModalViewController:self.myViewControllerProperty animated:YES];

dissmissModalViewController

viewDidUnload