DeleteOnSubmit（）和SubmitChanges（）不起作用。 没有异常或错误。 InsertOnSubmit（）工作正常

Question

I got this code to Delete a Category row from a Database. The Category has only 2 columns: Id and Name. It doesn't announce any errors. It just doesn't work.

If it worked, it should Redirect to Categories/Index . Instead, it shows Categories/Delete but now without any Category as parameter.

        public ActionResult Delete(int id)
        {
            var category = db.Categories.Where(r => r.Id == id).SingleOrDefault();
            return View(category); 
        }

        [HttpPost]
        public ActionResult Delete(Category category)
        {
            try
            {
                Category c = db.Categories
                    .Where(r => r.Id == category.Id)
                    .Single<Category>();
                db.Categories.DeleteOnSubmit(c);
                db.SubmitChanges();
                return RedirectToAction("Index");
            }
            catch
            {
                return View(category);
            }
        }

But this code for the Create action works just fine:

    public ActionResult Create()
    {
        Category c = new Category();
        return View(c);
    }

    [HttpPost]
    public ActionResult Create(Category category)
    {
        try
        {
            Category x = new Category
            {
                Name = category.Name
            };
            db.Categories.InsertOnSubmit(x);
            db.SubmitChanges();
            return RedirectToAction("Index");
        }
        catch
        {
            return View();
        }
    }

Answer 1

Turns out the row I wanted to test the Delete functionality on was referenced as a foreign key by another table in the database.

I tested deleting a row that was not referenced by any other table. Works just fine.