c# - DbContext 必须可转换为 System.Data.Entity.DbContext

Question

在我的应用程序中，我刚刚将 EntityFramework 更新到版本 6.0.2，现在我遇到了一些错误，这是我在更新我的应用程序之前没有发现的。

我有一个从 IdentityDbContext 类继承的 DbContext 文件。例如

public class DatePickerDbContext : IdentityDbContext<ApplicationUser>
{
    public DatePickerDbContext():base("DefaultConnection")
    {
    }
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
        modelBuilder.Entity<IdentityUser>().ToTable("Users");
        modelBuilder.Entity<ApplicationUser>().ToTable("Users");
        modelBuilder.Entity<IdentityRole>().ToTable("Roles");
    }
    public DbSet<License> Licenses { get; set; }
    public DbSet<AddressBook> AddressBooks { get; set; }
    public DbSet<AddressBookPerson> AddressBookPersons { get; set; }

    public DbSet<Appointment> Appointments { get; set; }

    public DbSet<Attendee> Attendees { get; set; }

    public DbSet<Response> Responses { get; set; } 

}

在我更新我的应用程序之前，下面一行完全没问题

 Database.SetInitializer<DatePickerDbContext>(new DatePickerDbInitializer());

datepickerdbinitializer类:

 public class DatePickerDbInitializer:CreateDatabaseIfNotExists<DatePickerDbContext>
    {
        protected override void Seed(DatePickerDbContext context)
        {
            InitializeDatePickerDbForEf(context);
            base.Seed(context);
        }

        private static void InitializeDatePickerDbForEf(DatePickerDbContext context)
        {
            var userManager = new UserManager<ApplicationUser>(new UserStore<ApplicationUser>(context));
            var roleManager = new RoleManager<IdentityRole>(new RoleStore<IdentityRole>());
            var licenseTrial = new License
            {
                Id = 1,
                Name = "Trial",
                Description = "Works for 14 days"
            };

            var licenseFull = new License
            {
                Id = 2,
                Name = "Full",
                Description = "Subscription based"
            };
            context.Licenses.Add(licenseTrial);
            context.Licenses.Add(licenseFull);

            var user = new ApplicationUser
            {
                UserId = new Guid(),
                UserName = "biplov",
                IsApproved = true,
                License = licenseFull,
                DateTimeRegistered = DateTime.UtcNow
            };

            if (!roleManager.RoleExists("Admin"))
            {
                roleManager.Create(new IdentityRole("Admin"));
            }

            var createUser = userManager.Create(user,"biplov");
            if (createUser.Succeeded)
            {
                userManager.AddToRole(user.Id,"Admin");
            }

        }
    }

but now I get a complain saying `The type DatePicker.Models.DatePickerDbContext must be convertible to System.Data.Entity.DbContext in order to use it as parameter 'TContext' in the generic method 'void System.Data.Entity.Database.SetInitializer<TContext>(IDatabaseInitialize<TContext>)'`
![enter image description here][1]

I still have another application in MVC5 from web called AspnetIdentitySample whose DbContext also inherits from IdentityDbContext<TUser> class but has no prob in global.asax's `Database.SetInitializer` method

    public class MyDbContext : IdentityDbContext<ApplicationUser>
    {
        public MyDbContext()
            : base("DefaultConnection")
        {
        }

        protected override void OnModelCreating(DbModelBuilder modelBuilder)
        {
            base.OnModelCreating(modelBuilder);

            // Change the name of the table to be Users instead of AspNetUsers
            modelBuilder.Entity<IdentityUser>()
                .ToTable("Users");
            modelBuilder.Entity<ApplicationUser>()
                .ToTable("Users");
        }

        public DbSet<ToDo> ToDoes { get; set; }

        public DbSet<MyUserInfo> MyUserInfo { get; set; }
    }

在 global.asax 中

Database.SetInitializer<MyDbContext>(new MyDbInitializer());//no error.

错误是因为我更新了我的 Entity Framework 并且新的 Entity Framework 中发生了一些变化吗？还是我做错了什么？未显示错误的 Entity Framework 版本为 6.1.0-alpha1

Answer 1

同样的事情发生在我身上，在我的例子中，是 ReSharper-cache 试图让我感到困惑。

我是这样修复的:

Tools -> Options -> ReSharper -> Options -> General -> Clear Caches