The model backing the 'ApplicationDbContext' context has changed since the database was created

Question

First of all, I have not seen this error anywhere else and I guess it's not a replicate so please read the whole situation first.

Everything was working just fine then I tried to update one of my model classes ( the App class and the update is now left commented ) which I will be listing below; and boom I had this ugly error.

---

The model backing the 'ApplicationDbContext' context has changed since the database was created. Consider using Code First Migrations to update the database (http://go.microsoft.com/fwlink/?LinkId=238269). at System.Data.Entity.CreateDatabaseIfNotExists1.InitializeDatabase(TContext context) at System.Data.Entity.Internal.InternalContext.<>c__DisplayClassf1.b__e() at System.Data.Entity.Internal.InternalContext.PerformInitializationAction(Action action) at System.Data.Entity.Internal.InternalContext.PerformDatabaseInitialization() at System.Data.Entity.Internal.LazyInternalContext.b__4(InternalContext c) at System.Data.Entity.Internal.RetryAction1.PerformAction(TInput input) at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabaseAction(Action1 action) at System.Data.Entity.Internal.LazyInternalContext.InitializeDatabase() at System.Data.Entity.Internal.InternalContext.GetEntitySetAndBaseTypeForType(Type entityType) at System.Data.Entity.Internal.Linq.InternalSet1.Initialize() at System.Data.Entity.Internal.Linq.InternalSet1.Include(String path) at System.Data.Entity.Infrastructure.DbQuery1.Include(String path) at System.Data.Entity.QueryableExtensions.Include[T](IQueryable1 source, String path) at System.Data.Entity.QueryableExtensions.Include[T,TProperty](IQueryable1 source, Expression1 path) at Microsoft.AspNet.Identity.EntityFramework.UserStore6.GetUserAggregateAsync(Expression1 filter) at Microsoft.AspNet.Identity.EntityFramework.UserStore6.FindByNameAsync(String userName) at Microsoft.AspNet.Identity.UserManager2.FindByNameAsync(String userName) at Microsoft.AspNet.Identity.UserManager`2.d__12.MoveNext() --- End of stack trace from previous location where exception was thrown --- at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) at ControlPanel.Web.Controllers.AccountController.d__2.MoveNext() in d:\Projects\FULL\Control Panel\ControlPanel.Web\Controllers\AccountController.cs:line 56

At first I thought it might be a migrations problem, so I dropped the database entirely, re-enabled the migrations, and added an Init migration and updated the database using

update-database -force -verbose

Everything goes well with no complaints, however, whenever I try to log in to my site I get the previous error. I did the migration thing about ten times without being able to solve the problem.

Here are my domain classes ( models ):

public class App
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public virtual int AppId { get; set; }
    //[Required]
    public virtual string FacebookId { get; set; }
    //[Required]
    public virtual string Secret { get; set; }      
    public virtual List<User> Users { get; set; }
    public virtual List<Post> Posts { get; set; }      
    //public virtual ApplicationUser Admin { get; set; }
}

public class Post
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public virtual int PostId { get; set; }
    public virtual string Content { get; set; }
    public virtual string Link { get; set; }
    public virtual string Image { get; set; }
    public virtual bool IsSpecial { get; set; }
    //[Required]
    public virtual App App { get; set; }
    //[Required]
    public virtual DateTime? PublishDate { get; set; }
}

public class User
{
    [Key]
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public virtual int UserId { get; set; }

    [MaxLength(500)]
    public virtual string FacebookId { get; set; }

    [MaxLength(500)]
    public virtual string Token { get; set; }

    //[Required]
    public virtual App App { get; set; }
}

Here are my IdentityModels:

public class ApplicationUser : IdentityUser
{
    public virtual List<App> Apps { get; set; }
    public bool? IsPremium { get; set; }
    [DataType(DataType.Date)]
    public DateTime? LastPublishDateTime { get; set; }
}

public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
    public ApplicationDbContext()
        : base("dCon")
    {
    }
    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        base.OnModelCreating(modelBuilder);
        modelBuilder.Entity<IdentityUser>().ToTable("Admins");
        modelBuilder.Entity<ApplicationUser>().ToTable("Admins");
        modelBuilder.Entity<IdentityUserRole>().ToTable("AdminRoles");
        modelBuilder.Entity<IdentityUserLogin>().ToTable("Logins");
        modelBuilder.Entity<IdentityUserClaim>().ToTable("Claims");
        modelBuilder.Entity<IdentityRole>().ToTable("Roles");
    }
}

Answer 1

Just in case anyone else stumbles upon this that was doing a database first implementation like me.

I made a change by extending the ApplicationUser class, adding a new field to the AspNetUsers table, and then had this error on startup.

I was able to resolve this by deleting the record created in the __MigrationHistory table (there was only one record there) I assume EF decided that I needed to update my database using the migration tool - but I had already done this manually myself.

Answer 2

This worked for me - no other changes required.

DELETE FROM [dbo].[__MigrationHistory]

Answer 3

This post fixed my issue. It's all about adding the following line in Application_Start() in Global.asax :

Database.SetInitializer<Models.YourDbContext>(null);

However it cause database recreation for every edit in your model and you may loose your data.

Answer 4

If you delete the "[__MigrationHistory]" table from your "database > System Tables" then it will work.

Answer 5

It was such a strange error,, It wasn't my error at the end, it was Microsoft's,, I installed the Entity framework the " pre-release" version and it was responsible for this error,, when i upgraded to the stable release it disapperared,, thank you everyone believe me when i asked this question i searched like for a week or so for its solution so i am pretty sure that this problem isn't anywhere else : the version of entity framework.dll that caused the problem was 6.0.2 if it helps.