Unable to resolve service for type 'UnitOfWork' while attempting to activate MyController

I have Implemented a Generic Repository Pattern and UnitOfWork but I get an InvalidOperationException: Unable to resolve service for type 'UnitOfWork' while attempting to activate MyController

Here is my DBContext:

public class DBContext : DbContext
{
        public DBContext()
    {
       
    }
  protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer(@"Server=(localdb)\mssqllocaldb;Database=Nashrieh2");
    }
    public DbSet<User> Users { get; set; }
}

Here is User.cs class

public class User
{
    [Key]
    public string UserID { get; set; }
    public string Role { get; set; }
    public string UserName { get; set; }
    [Required(ErrorMessage = "Choose a password for your account")]
    public string Password { get; set; }
}

Here is my Repository Pattern GenericRepository.cs:

  public class GenericRepository<T> where T : class

{
    internal DBContext _context;

    public GenericRepository(DBContext context)
    {
        this._context = context;
    }
   public IEnumerable<T> GetList()
    {
      return  _context.Set<T>().ToList();
    }
    public async Task<IEnumerable<T>> ToListAsync()
    {
        return await _context.Set<T>().ToListAsync();
    }
    public virtual T Find(object id)
    {
        return _context.Set<T>().Find(id);
    }
  public virtual async Task AddAsync(T entity)
    {
         await _context.Set<T>().AddAsync(entity);
    }

Here is my unit of work:

public class UnitOfWork : IDisposable
{
    private DBContext _context;

    public UnitOfWork(DBContext context)
    {
        _context = context;
    }
    public GenericRepository<User> Users
    {
        get
        {

            if (this.user == null)
            {
                this.user = new GenericRepository<User>(_context);
            }
            return user;
        }
    }
    public async Task SaveChangesAsync()
    {
        await _context.SaveChangesAsync();
    }
    public void SaveChanges()
    {
        _context.SaveChanges();
    }
    private bool disposed = false;

    protected virtual void Dispose(bool disposing)
    {
        if (!this.disposed)
        {
            if (disposing)
            {
                _context.Dispose();
            }
        }
        this.disposed = true;
    }

    public void Dispose()
    {
        Dispose(true);
        GC.SuppressFinalize(this);
    }
}

Here is my controller:

  public class MyController : Controller
{
 private UnitOfWork _unitOfWork;
    public MyController(UnitOfWork unitOfWork)
    {
        _unitOfWork = unitOfWork;
    }
}

An Exception in occurred

InvalidOperationException: Unable to resolve service for type 'UnitOfWork' while attempting to activate MyController