asp.net – 在App_Start中初始化和播种Identity的DbContext

首先编辑DbContextInitializer：

public class DbContextInitializer : DropCreateDatabaseIfModelChanges<AppDbContext> {

  protected override void Seed(AppDbContext context) {

    // remove this,because the OWIN context does not yet exist:
    //var userManager = HttpContext.Current.GetOwinContext().GetUserManager<AppUserManager>();
    //var roleManager = HttpContext.Current.GetOwinContext().Get<AppRoleManager>();

    // and replace it with:
    var userManager = new AppUserManager<AppUser>(new UserStore<AppUser>(context));
    var roleManager = new AppRoleManager<IdentityRole>(new RoleStore<IdentityRole>(context));

    // ... etc. ...

    base.Seed(context);
  }

}

然后编辑AppDbContext：

public class AppDbContext : IdentityDbContext<AppUser> {

  // no change: this static factory method is called in OWIN init
  public static AppDbContext Create() { return new AppDbContext(); }

  // no change: this static ctor called the first time this type is referenced
  static AppDbContext() { Database.SetInitializer<AppDbContext>(new DbContextInitializer()); }

  // changed: made ctor private
  private AppDbContext() : base("name=DefaultConnection",false) { }

  // add this: forces the initializer to run,even if it's already been run
  public static void init() { Create().Database.Initialize(true); }

}

最后编辑Global.asax.cs：

protected void Application_Start() {
  // ... etc.
  DbContext.init();                            // force initializer to run
  // ... etc.
  }

结果是db不再是延迟创建/延迟加载的,而是在Application_Start中初始化.这有必要吗？不.但现在我的所有初始化代码都出现在一个地方,并且在调试时更容易跟踪事情.