0
public class UserRepository
{
    private readonly List<Users> _user;
    public UserRepository()
    {
        _user = new List<Users>();

        _user.Add(new Users
        {
            Id=1,
            FullName="bijan pooladian",
            Address="asalooye",
            Email="bpooladian@gmail.com",
            PhoneNumber="09014547885",
            Job="engineer"
        });

        _user.Add(new Users
        {
            Id = 2,
            FullName = "Hadi pooladian",
            Address = "shiraz",
            Email = "hadipooladian@gmail.com",
            PhoneNumber = "09028912957",
            Job = "Programmer"
        });

        _user.Add(new Users
        {
            Id = 2,
            FullName = "bahram pooladian",
            Address = "firoozabad",
            Email = "bijanpooladian@gmail.com",
            PhoneNumber = "09172221458",
            Job = "sellman"
        });
    }
    public List<UserListViewModel> GetUserList()
    {
        List<UserListViewModel> user = _user.Select(p => new UserListViewModel
        {
            Email = p.Email,
            Id = p.Id
        }).ToList();
        return user;
    }

    public UserDetailViewModel Find(int id)
    {
        var user = _user.Where(p => p.Id == id).FirstOrDefault();
        return new UserDetailViewModel()
        {
          Address=user.Address,
          Id=user.Id,
          FullName=user.FullName,
          Job= user.Job,
          Email=user.Email,
          PhoneNumber=user.PhoneNumber
        };
    }
}

}

this is my Repository class the error System.NullReferenceException: 'Object reference not set to an instance of an object.' occer in my Find metod and I dont really have no idea how to fix it, please someone help me. in this project I want to show information by using view component.

hadi
  • 1
  • 1
  • 1
    `FirstOrDefault()` can return `null`, so check for that. – VDWWD Aug 02 '22 at 08:27
  • Set the breakpoint after `var user = _user.Where(p => p.Id == id).FirstOrDefault();` and check if `user` is null. If it is, then `Address=user.Address` will throw NullReferenceException – virouz98 Aug 02 '22 at 08:40

0 Answers0