数据未显示在tableview Swift CoreData中

import UIKit
import CoreData

class ViewController: UIViewController, UITableViewDataSource, NSFetchedResultsControllerDelegate {
    
    @IBOutlet weak var tableView: UITableView!
    
    var fetchedResultsController: NSFetchedResultsController<NSManagedObject>!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // 初始化NSFetchedResultsController
        let fetchRequest: NSFetchRequest<NSManagedObject> = NSFetchRequest(entityName: "YourEntityName")
        let sortDescriptor = NSSortDescriptor(key: "yourSortKey", ascending: true)
        fetchRequest.sortDescriptors = [sortDescriptor]
        
        let context = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext
        fetchedResultsController = NSFetchedResultsController(fetchRequest: fetchRequest, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
        fetchedResultsController.delegate = self
        
        // 执行查询
        do {
            try fetchedResultsController.performFetch()
        } catch {
            print("Fetch error: \(error.localizedDescription)")
        }
    }
    
    // MARK: - UITableViewDataSource
    
    func numberOfSections(in tableView: UITableView) -> Int {
        return fetchedResultsController.sections?.count ?? 0
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        guard let sections = fetchedResultsController.sections else {
            return 0
        }
        let sectionInfo = sections[section]
        return sectionInfo.numberOfObjects
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCell(withIdentifier: "YourCellIdentifier", for: indexPath)
        let object = fetchedResultsController.object(at: indexPath)
        
        // 根据数据设置单元格内容
        // cell.textLabel?.text = object.value(forKey: "yourAttributeKey") as? String
        
        return cell
    }
    
    // MARK: - NSFetchedResultsControllerDelegate
    
    func controllerWillChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
        tableView.beginUpdates()
    }
    
    func controllerDidChangeContent(_ controller: NSFetchedResultsController<NSFetchRequestResult>) {
        tableView.endUpdates()
    }
    
    // 其他NSFetchedResultsControllerDelegate方法省略
    
}