Update operation not working in MVC5 with EF - asp.net-mvc

Question

Please Help
This is how i'm updating....
[HttpPost, ActionName("Edit")]
public ActionResult Edit(Students model)
{
if (ModelState.IsValid)
{
using (DbAccess db = new DbAccess())
{
var ID=db.students.Find(model.id);
db.Entry(ID).State = EntityState.Modified;
//ID.name = model.name;
//ID.address = model.address;
//ID.age = model.age;
//ID.email = model.email;
//ID.isActive = model.isActive;
db.SaveChanges();
}
}
return View(model);
}
In the above code when i update separately than it works well but when i use db.Entry(...)...... than it doesn't work for me and it also not shows any error

Answer 1

You can try...
[HttpPost, ActionName("Edit")]
public ActionResult Edit(Students model)
{
if (ModelState.IsValid)
{
using (DbAccess db = new DbAccess())
{
var ID = db.students.Find(model.id);
//db.Entry(ID).State = EntityState.Modified;
ID.name = model.name;
ID.address = model.address;
ID.age = model.age;
ID.email = model.email;
ID.isActive = model.isActive;
db.SaveChanges();
}
}
return View(model);
}

Answer 2

When you are doing var ID=db.students.Find(model.id);
You don't need to use
db.Entry(ID).State = EntityState.Modified;
Because when you do Find you have real object of your dbContext, when you make changes on it(except on it primary key of course), your SaveChanges will detect it and update it accordingly.
You need to set State only when you are doing something like this
Students students = new Students(); //a new object which is not created using `Find`
students.name = "Heartlion";
students.address = "address text";
db.Entry(students).State = EntityState.Modified;
db.SaveChanges();

Answer 3

just replace this:
db.Entry(ID).State = EntityState.Modified;
//ID.name = model.name;
//ID.address = model.address;
//ID.age = model.age;
//ID.email = model.email;
//ID.isActive = model.isActive;
with:
UpdateModel(ID);
and you'll be fine;
In order for your method to work, you need to do like this:
db.Students .Attach(ID);
var entry = db.Entry(ID);
entry.State = EntityState.Modified;
entry.Property(x => x.name).IsModified = true;
entry.Property(x => x.address).IsModified = true;
....
db.SaveChanges();
Basically you need to attach the updated model then to tell to the context, which props are modified.
I have in my repository, another method which I use in some situations, when the update is not done in the controller, the method is:
public void Update(TEntity newEntity)
{
var oldEntity = Context.Set<TEntity>().Find(newEntity.Id);
Context.Entry(oldEntity).CurrentValues.SetValues(newEntity);
}
In this method, the newEntity is comming from the view, and the oldEntity is from the context.
UpdateModel can be used only in controllers, when I call the update outside of the controller, I use the above method. I prefer this methods because I do not need to explicitly tell which props are been modified. When you have a form with 10 props, and user is updating only 3 or 4, you need a lot of logic to determine which were modified.
PS - my entities are all implementing IEntityId, which is an interface with common properties, like Id, UpdateDate, InsertDate ..., this is why I can call newEntity.Id