c# - 如何在没有 TryUpdateModel() 的情况下更新数据库

Question

我一直在使用 MVC4，我只需调用 TryUpdateModel();

即可将我的实体更新到数据库

例子(MVC4)

public ActionResult Edit(User user)
{
    var userDb = _db.Users.Single(x => x.Id == user.Id);

    if (TryUpdateModel(userDb))
    {
        _db.SaveChanges(); // Done, database is updated
    }
}

现在我正在使用 NancyFX 作为 API，但那里没有 TryUpdateModel() 函数。

Put["/"] = p =>
{
    var user = this.Bind<User>();
    var result = this.Validate(user);

    if (!result.IsValid)
    {
        return Response.AsJson(result, HttpStatusCode.BadRequest);
    }

    // How to update my database here? No TryUpdateModel() function is avialable.

    return Response.AsJson(user, HttpStatusCode.OK);
};

Answer 1

基于 https://github.com/NancyFx/Nancy/wiki/Model-binding ，我希望以下内容起作用:

// get a fresh copy of the user model for the purposes of getting the id (there may be a simpler way to do this) 
var rawUser = this.Bind<User>();
// read the user from the db
var user = db.Users.Single(u => u.Id == rawUser.Id);
// bind again, but using the db user as the target
this.BindTo(user);
// commit (I think EF may be smart enough not to do anything if BindTo() didn't actually change anything)
db.SaveChanges();