Object 在类型为错误的对象上找不到属性？

我发现了错误

在第3行“DetailViewController”类型的对象上未找到属性“selectedCollege”

DetailViewController *dvController = [[DetailViewController alloc] initWithNibName:@"DetailView" bundle:[NSBundle mainBundle]];
dvController.selectedCollege = selectedCollege;
[self.navigationController pushViewController:dvController animated:YES];
[dvController release];
dvController = nil;