Question

It is works:

[HttpPost] 
public ActionResult Delete(int id, Products p) 
{
   DataContext.Products.DeleteObject(
      DataContext.Products.SingleOrDefault(t => t.Id == id));
   return RedirectToAction("Index");
}

And it is works too:

[HttpPost] 
public ActionResult Edit(Products p) 
{
  DataContext.ApplyCurrentValues("Products",p); 
  return RedirectToAction("Index"); 
}

But this not working:

[HttpPost]
public ActionResult Delete(Products p)
{
   DataContext.Products.DeleteObject(p);
   return RedirectToAction("Index");
}

Why?

Answer 1

Because you must first Attach object before you can delete it:

[HttpPost]
public ActionResult Delete(Products p)
{
   DataContext.Products.Attach(p);
   DataContext.Products.DeleteObject(p);
   DataContext.SaveChanges();
   return RedirectToAction("Index");
}