这很奇怪，但这里所有的答案对我来说都没用。 对于我来说，有效的初始化器

MigrateDatabaseToLatestVersion

以下是我的解决方案(我知道，它可以简单得多，但这就是我使用它的方式):

class MyDbMigrateToLatest : MigrateDatabaseToLatestVersion<MyDbContext, Configuration>
{
}

public class MyDbContext: DbContext
{
    public MyDbContext() : base("DbName")
    {
        SetInitializer();
    }

    public MyDbContext(string connString) : base(connString)
    {
        SetInitializer();
    }

    private static void SetInitializer()
    {
        if (ConfigurationManager.AppSettings["RebuildDatabaseOnStart"] == "true")
            Database.SetInitializer(new MyDbInitializerForTesting());
        else
            Database.SetInitializer(new MyDbMigrateToLatest());
    }
}

public sealed class Configuration : DbMigrationsConfiguration<MyDbContext>
{
    public Configuration()
    {
        AutomaticMigrationsEnabled = true;
    }

    protected override void Seed(MyDbContext context)
    {
        // Whatever
    }
}

MyDbInitializerForTesting只是继承自DropCreateDatabaseAlways，所以在某些特定的情况下(测试)，整个数据库被重建。否则，它已迁移到最新版本。

我的来源:https://msdn.microsoft.com/en-us/data/jj591621.aspx#specific

现在是:

protected override void OnModelCreating(DbModelBuilder modelBuilder)
{
    Database.SetInitializer<YourDbContext>(null);
    base.OnModelCreating(modelBuilder);
}

在你的YourDbContext.cs文件中。

I had the same issue - re-adding the migration and updating the database didn't work and none of the answers above seemed right. Then inspiration hit me - I'm using multiple tiers (one web, one data, and one business). The data layer has the context and all the models. The web layer never threw this exception - it was the business layer (which I set as console application for testing and debugging). Turns out the business layer wasn't using the right connection string to get the db and make the context. So I added the connection string to the app config of the business layer (and the data layer) and viola it works. Putting this here for others who may encounter the same issue.

好建议，但并非在所有情况下都如此准确。我算出一个。 请确保您在Visual Studio中使用PM窗口运行“enable-migrations”，迁移文件夹将添加到您的项目中。

确保添加到文件夹中的两个c#类文件将包含所有模型及其各自的属性。

如果您拥有所有这些，就构建解决方案，并发布部署。

逻辑是不能覆盖现有元数据，因为应用程序没有元数据来替换当前元数据。结果，你会得到这样的错误“支持上下文的模型自数据库创建以来已经改变了”

刚刚找到答案，想在这里更新。只需要做以下事情。

public class AddressBook: DbContext
{
   protected override void OnModelCreating(ModelBuilder modelBuilder)
   {
    modelBuilder.IncludeMetadataInDatabase = false;
   }
}

此修复在CTP5之后不再有效。

你必须执行database。setinitializer <YourContext>(null);