我正在一个网站上,我想从数据库中读出所有用户。 但是我得到了
NullReferenceException:对象引用未设置为对象的实例。
当我使用仅返回1行的查询时,它可以正常工作。但是,如果返回的行多于一行,则会出现异常。
content
Startup.cs
var appUser = _context.ApplicationUser.Where(u => u.NormalizedUserName == "MARK"); //OK
var allUser = _context.ApplicationUser.Where(u => u.NormalizedUserName != "MARK"); //NullReferenceException: Object reference not set to an instance of an object
var appUser2 = await _userManager.FindByNameAsync("MARK"); //OK
var allUser2 = await _userManager.Users.ToListAsync(); //NullReferenceException: Object reference not set to an instance of an object
ApplicationUser.cs
services.AddDbContext<WebShopContext>(options =>
options.UseSqlServer(Configuration.GetConnectionString("DevConnection"))
);
services.AddIdentity<ApplicationUser, ApplicationRole>()
.AddEntityFrameworkStores<WebShopContext>();
DbContext:
public class ApplicationUser : IdentityUser
{
public ApplicationUser() : base() { }
public ApplicationUser(string userName) : base(userName) { }
...
}
我在做什么错了?