创建数据库后，支持“DataContext”上下文的模型已更改 [英] The model backing the 'DataContext' context has changed since the database was created

问题描述

我正在尝试使用代码优先与迁移。即使我的模型目前没有任何变化，我也有异常。当我添加一个迁移时，上下文是空的，但是我收到如下消息的运行时错误：

I am trying to use Code First with Migrations. Even though there are no current changes to my model, I'm getting an exception. When I add a migration, the up and down are empty, but I get a runtime error with the message as follows:

在
EntityFramework.dll中键入'System.InvalidOperationException'，但未在用户代码中处理

An exception of type 'System.InvalidOperationException' occurred in EntityFramework.dll but was not handled in user code

附加信息：支持MyDataContext上下文$ b的模型$ b自数据库创建以来已更改。考虑使用Code First
迁移来更新数据库（ http://go.microsoft.com/fwlink/ ？

Additional information: The model backing the 'MyDataContext' context has changed since the database was created. Consider using Code First Migrations to update the database (http://go.microsoft.com/fwlink/?

我的架构如下：

• 包含上下文，流体配置和迁移代码的DataAccess项目


• 包含poco类的模型项目


• Web API和MVC项目每个都包含各自web.config文件中的连接字符串。

此外，我还有以下代码：

Additionally I have the following code:

DbInitializer

DbInitializer

public static MyDataContext Create()
{
   Database.SetInitializer(new MigrateDatabaseToLatestVersion<MyDataAccess.MyDataContext, MyDataAccess.Migrations.Configuration>());
   return new MyDataContext(ConfigurationManager.ConnectionStrings["MyDataContext"].ConnectionString, null);
}

我使用AutomaticMigrationsEnabled = false;在迁移配置构造函数中，正如我所理解的那样，这将允许（并且要求）更好地控制迁移应用时的控制。我也尝试将其设置为true，但结果相同。

I started with AutomaticMigrationsEnabled = false; in the migration Configuration constructor, as it was my understanding that this would allow (and require) me to have more control over when migrations were applied. I have also tried setting this to true but with the same result.

我收到此错误时添加了新的迁移，Up方法为空。我将数据库更新为此新迁移，并在_migrationHistory表中创建了一条记录，但是当我尝试运行应用程序时仍然收到错误。另外，种子数据没有添加到数据库中。

I added a new migration upon receiving this error, and the Up method was empty. I updated the database to this new migration, and a record was created in the _migrationHistory table, but I still receive the error when I attempt to run the application. Also, the seed data was not added to the database.

protected override void Seed(MyDataAccess.MyDataContext context)
{
            IdentityResult ir;

            var appDbContext = new ApplicationDbContext();
            var roleManager = new RoleManager<IdentityRole>(new RoleStore<IdentityRole>(appDbContext));
            ir = roleManager.Create(new IdentityRole("Admin"));
            ir = roleManager.Create(new IdentityRole("Active"));
            ir = roleManager.Create(new IdentityRole("InActive"));

            var userNamager = new UserManager<User>(new UserStore<User>(appDbContext));

            //  assign default admin
            var admin = new User { UserName = "administrator", Email = "[e-mail]" };
            ir = userNamager.Create(admin, "myp@55word");

            ir = userNamager.AddToRole(admin.Id, "Admin");
 }

其中

public class ApplicationDbContext : IdentityDbContext<User>
{
    public ApplicationDbContext()
        : base("MyDataContext", throwIfV1Schema: false)
    {
    }
    ...

问题：如果Add-Migration在模型中没有看到任何更改，为什么在运行时会收到此错误？为什么种子代码没有被击中？如何解决这个问题，或者如果不能确定，我该如何进一步确定根本原因？

The question: If Add-Migration isn't seeing any change in the model, why do I get this error when I run? Why isn't the seed code being hit? How do I fix this, or if that can't be determined, how do I further determine the root cause?

推荐答案

为我工作。

转到软件包管理器控制台和运行 - 更新 - 数据库--force

Go to Package Manager Console and Run - Update-Database -force

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