Question

场景

我有2个表，人员及其活动，每次创建活动时，我还必须选择一个属于该活动的人。现在如何保存/始终更新人 personId 的 * LatestActivityId 记录？

这是因为我想跟踪此人的上一次活动数据。

非常感谢您的输入

这是我到目前为止所拥有的：

    [HttpPost]

   public ActionResult Create([Bind(Include = "PersonId" + "," + "ActivityTypeId")] dbo_Activities dbo_Activities)

   {
    if (ModelState.IsValid) {

     // >>STUCK HERE<< //int SaveAsLatestActivity = db.dbo_Businesses.Max(p => p.ActivityId);

     db.dbo_Activities.Add(dbo_Activities);

     db.SaveChanges();

     return RedirectToAction("Index");
    }

    // ComboBox >> selects person

    ViewData["PersonId"] = new SelectList(db.dbo_Businesses, "PersonId", "FullName", dbo_Activities.PersonId);

    return View(dbo_Activities);
   }

我的活动模型

 public class dbo_Activities
    {
        [Key]
        [Column(Order = 0)]
        [Required]
        [Display(Name = "Activity Id")]
        public Int32 ActivityId { get; set; }

        [Display(Name = "Person Id")]
        public Int32? PersonId { get; set; }
}

Answer 1

您拥有PersonId，因此在创建活动并获取ID后，从人员表中查询人员，将LatestActivityId设置为刚创建的活动的ID，然后保存此人。您尚未发布完整的模型，因此我对某些属性的调用和模型的名称进行了一些假设，但应该看起来像这样：

[HttpPost]
public ActionResult Create([Bind(Include = "PersonId" + "," + "ActivityTypeId")] dbo_Activities dbo_Activities)
{
    if (ModelState.IsValid) {
        db.dbo_Activities.Add(dbo_Activities);
        db.SaveChanges();

        //set LatestActivityId on the person to the ActivityId of the entry that was just created
        var person = db.dbo_Persons.Single(x => x.Id == dbo_Activities.PersonId);
        person.LatestActivityId = dbo_Activities.ActivityId;
        db.SaveChanges();

        return RedirectToAction("Index");
    }

    ViewData["PersonId"] = new SelectList(db.dbo_Businesses, "PersonId", "FullName", dbo_Activities.PersonId);

    return View(dbo_Activities);
}

EF如何更新相关表值

1 个答案: