MVC 4 Add a child record to existing parent - entity-framework

Question

How do you add a child to a parent record in MVC 4 using EF?
I've got a grid showing News. I need to add Updates that are children records of those. One DB table has News, another has Updates. They are linked by NewsID in each table.
NEWS MODEL
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int NewsId { get; set; }
public string Body { get; set; }
//other fields
UPDATES MODEL
[Key]
[DatabaseGeneratedAttribute(DatabaseGeneratedOption.Identity)]
public int NewsUpdateId { get; set; }
public int NewsId { get; set; }
public string Body { get; set; }
//other fields
NEWS INDEX VIEW (only partly posted here; it's a grid showing these detail rows)
#foreach (var item in Model) {
<tr>
<td>#Html.ActionLink(item.Headline, "Details", new { id=item.NewsId })</td>
<td>#Html.Raw(item.Body.Remove(300))...</td>
//other fields
<td>#Html.ActionLink("Edit", "Edit", new { id=item.NewsId })</td>
//WOULD LIKE ANOTHER LINK GOING TO "UPDATE" SCREEN TO ADD CHILD UPDATES, PASSING IN THE PARENT ID
</tr>
}
CONTROLLER (right now)
public ActionResult Update()
{
return View();
}
But of course when I'm on that Update screen and save, there's no NewsID to save into Updates and it fails. How can I pass NewsID from the index screen/grid into my "Create Update" screen, then later retrieve it while on that Update screen and add it to my save action?
UPDATE
Since no one has any idea how to do this, I'm making it up as I go along without luck.
I've tried using the NewsUpdate screen like an Edit where you pass the id value. The difference is that, for Edit, you're editing that record. For this NewsUpdate, I'm adding a NewsUpdate, which is a child record of News, so I have the existing NewsID and need to pass it to my NewsUpdate screen and ultimately use it to set NewsUpdate.NewsID to it.
When I save the NewsUpdate screen, the model is invalid because it is missing, so I tried to this to set it:
var NewsID = Request.Url.PathAndQuery.ToString(); //grab it from url News/Update/8
NewsID = NewsID.Replace("/News/Update/", ""); //results in NewsID = 8
NewsUpdate.NewsID = Convert.ToInt32(NewsID);
This works, but the model is still invalid right after this. So this is no good.

Answer 1

Got it.
public ActionResult Update(int id = 0)
{
NewsUpdate myUpdate= db.NewsUpdate.Create(); //create empty child model
myUpdate.NewsID = id; //set my parent's ID on the child model
View(myUpdate); //send child model to child's create screen aka "NewsUpdate"
}
This passes my parent id in the child model and the rest of the NewsUpdate screen, which is like a standard Create screen, just functions as usual.