linq to sql question , why my change is not saved? - asp.net-mvc

Question

this is my first mvc 3 project, i am using linq to sql.
public ActionResult Edit(int ID)
{
try
{
Tutorial tut = reposi.Tutorials.Single(d => d.TutorialID == ID);
return View(tut);
}
catch
{
return RedirectToAction("List");
}
}
[HttpPost]
public ActionResult Edit(Tutorial tut)
{
if (ModelState.IsValid)
{
//tut.TutorialID = ID;
tut.EditDate = DateTime.Now;
tutContext.SubmitChanges();
return RedirectToAction("List");
}
else
{
return View(tut);
}
}
after I click on the "Edit" button, It takes me back to list page, and changes are not saved. still old values.

Answer 1

You need to first get the Tutorial from your database, then make the changes, then SubmitChanges().
[HttpPost]
public ActionResult Edit(Tutorial tut)
{
if (ModelState.IsValid)
{
Tutorial t = tutContext.get(tut.Id);
//tut.TutorialID = ID;
t.EditDate = DateTime.Now;
tutContext.SubmitChanges();
return RedirectToAction("List");
}
else
{
return View(tut);
}
}
Note, your tutContext.get(tut.Id); may be different depending on your implementation.

Answer 2

tut.EditDate = DateTime.Now;
tutContext.SubmitChanges();
return RedirectToAction("List");
Your tutorial object is not managed by db context yet. so the context didn't save the object change when you change the tut object and invoke tutContext.SubmitChanges().
First thing first, you must lookup the tutorial object from the context.
Tutorial tut = ctx.Tutorials.Single(d => d.TutorialID == ID);
after you get the tuts object form the tuts context, that tuts object is managed by the db context. then you can modify the tut object and submit the changes.
Tutorial tut = ctx.Tutorials.Single(d => d.TutorialID == tut.ID);
tut.EditDate = DateTime.Now;
ctx.SubmitChanges();
You need this in the [HttpPost]

Answer 3

When you debug, are you reaching the Post action in the controller? Make sure your form action is set to POST instead of GET.