How to assign pk values from the controllerp - entity-framework

Question

ArticleIDX is the primary key.
I would like to assign this primary key to Family.
However, the primary key does not seem to be assigned a Family value because the create method is executed and incremented.
What should I do in this case?
[HttpPost]
public ActionResult Create(Articles article)
{
try
{
**article.Family = article.ArticleIDX;**
article.Parent = 0;
article.Depth = 0;
article.Indent = 0;
article.ModifyDate = DateTime.Now;
article.ModifyMemberID = User.Identity.Name;
db.Articles.Add(article);
db.SaveChanges();
}
ViewBag.Result = "OK";
}
catch (Exception ex)
{
Debug.WriteLine("Board");
Debug.WriteLine(ex.ToString());
ViewBag.Result = "FAIL";
}
return View(article);
}
public partial class Articles
{
[Key]
public int ArticleIDX { get; set; }
public int? Family { get; set; }
public int? Depth { get; set; }
public int? Indent { get; set; }
public int? Parent { get; set; }
[StringLength(200)]
public string Title { get; set; }
[Column(TypeName = "text")]
public string Contents { get; set; }
[StringLength(50)]
public string Category { get; set; }
[StringLength(20)]
public string ModifyMemberID { get; set; }
public DateTime? ModifyDate { get; set; }
public virtual Members Members { get; set; }
}

Answer 1

Because, primary key is not generated before inserting. You should insert the row first and assign the generated primary key after.
article.Family = 0;
article.Parent = 0;
article.Depth = 0;
article.Indent = 0;
article.ModifyDate = DateTime.Now;
article.ModifyMemberID = User.Identity.Name;
db.Articles.Add(article);
db.SaveChanges();
article.Family = article.ArticleIDX;//Update the Family after primary key generated
db.SaveChanges();