سلام با کد ذیل _userStore واسه من نال بر میگردونه
using System.Data.Entity; using System.Threading.Tasks; using Microsoft.AspNet.Identity.EntityFramework; using SmartMarket.Core.Domain.Members; using SmartMarket.Data; namespace SmartMarket.Services.Members { /// <summary> /// The ApplicationUserStore Class /// </summary> public class ApplicationUserStore : UserStore<User, Role, int, UserLogin, UserRole, UserClaim>, IApplicationUserStore { #region Fields (1) private readonly IDbSet<User> _userStore; #endregion Fields #region Constructors (2) /// <summary> /// Initializes a new instance of the <see cref="ApplicationUserStore" /> class. /// </summary> /// <param name="dbContext">The database context.</param> public ApplicationUserStore(DbContext dbContext) : base(dbContext) { } /// <summary> /// Initializes a new instance of the <see cref="ApplicationUserStore"/> class. /// </summary> /// <param name="context">The context.</param> public ApplicationUserStore(IdentityDbContext context) : base(context) { _userStore = context.Set<User>(); } #endregion Constructors #region Methods (2) // Public Methods (2) /// <summary> /// Adds to previous passwords asynchronous. /// </summary> /// <param name="user">The user.</param> /// <param name="password">The password.</param> /// <returns></returns> public Task AddToPreviousPasswordsAsync(User user, string password) { user.PreviousUserPasswords.Add(new PreviousPassword { UserId = user.Id, PasswordHash = password }); return UpdateAsync(user); } /// <summary> /// Finds the by identifier asynchronous. /// </summary> /// <param name="userId">The user identifier.</param> /// <returns></returns> public override Task<User> FindByIdAsync(int userId) { return Task.FromResult(_userStore.Find(userId)); } #endregion Methods /// <summary> /// Creates the asynchronous. /// </summary> /// <param name="user">The user.</param> /// <returns></returns> public override async Task CreateAsync(User user) { await base.CreateAsync(user); await AddToPreviousPasswordsAsync(user, user.PasswordHash); } } }