These are my model classes.
public class Survey
{
[Key]
public int SurveyID { get; set; }
[Required]
public string Title { get; set; }
[DataType(DataType.Text)]
[Required]
public string Description { get; set; }
public virtual Category Category { get; set; }
}
public class Category
{
[Key]
public int CategoryID { get; set; }
public string CategoryText { get; set; }
}
In the edit action of the SurveyController
the survey properties are updating but not the category.
Here is the edit action code.
[HttpPost]
[ValidateAntiForgeryToken]
public ActionResult Edit(Survey survey)
{
db.Database.Log = s => Debug.WriteLine(s);
if (ModelState.IsValid)
{
db.Entry(survey).State = EntityState.Modified;
db.SaveChanges();
return RedirectToAction("Index");
}
return View(survey);
}
Entity framework by default does not update the navigation properties. EF only knows/tracks the changes in the properties you explicitly update. EF can only save child objects if the parent object is retrieved with the same context.
As a solution you need to explicitly iterate over your child properties and set its state to modified.
foreach (var childModel in model.Children)
{
var existingChild = existingParent.Children
.Where(c => c.Id == childModel.Id)
.SingleOrDefault();
if (existingChild != null)
_dbContext.Entry(existingChild).CurrentValues.SetValues(childModel);
}
Update
var child = new ChildEntity() {Id = 1};
child.ParentEntityId = 1; // Assigning FK
context.Childs.Attach(child);
context.Entry(child).State = EntityState.Modified;
context.SaveChanges();
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