更新我的模型然后重新评估是否有效?

如果缺少的值是模型所必需的,但在绑定之后才提供,则可能需要从 ModelState .

[HttpPost, Authorize]
public ActionResult Thread(int id, string groupSlug, Comment comment, string submitButton)
{
  comment.UserID = UserService.UID;
  comment.IP = Request.UserHostAddress;

  //add these two lines
  ModelState["comment.UserID"].Errors.Clear();
  ModelState["comment.IP"].Errors.Clear();

  UpdateModel(comment); //throws invalidoperationexception
  if (ModelState.IsValid) // returns false if i skip last line
  {
    //save and stuff
    //redirect
  }
  //return view
}

我使用的是ASP.NET Core1.0.0和异步绑定,解决方案是使用ModelState.Remove并传递属性名(不带对象名)。

[HttpPost]
[ValidateAntiForgeryToken]
public async Task<IActionResult> Submit([Bind("AerodromeID,ObservationTimestamp,RawObservation")] WeatherObservation weatherObservation)
{
    weatherObservation.SubmitterID = this.User.FindFirst(ClaimTypes.NameIdentifier)?.Value;
    weatherObservation.RecordTimestamp = DateTime.Now;

    ModelState.Remove("SubmitterID");

    if (ModelState.IsValid)
    {
        _context.Add(weatherObservation);
        await _context.SaveChangesAsync();
        return RedirectToAction("Index", "Aerodrome");
    }
    return View(weatherObservation);
}

在使用.NET核心之前 Validate(TEntity entity) 假设您将缺少的必需属性设置为实体。

  ModelState.Clear();
  Validate(entity);
  if (!ModelState.IsValid) {}

TryValidateModel 而不是 ModelState.IsValid 请参见: https://docs.microsoft.com/en-us/aspnet/core/mvc/models/validation?view=aspnetcore-5.0