如何在ASP.NET MVC4中正确进行编辑操作？

Question

I'm trying to make an update this way :

[HttpPost]
        [ValidateAntiForgeryToken]
        public ActionResult Modifier(OSModel os)
        {    
            if (ModelState.IsValid)
            {
                _db.Entry(os).State = EntityState.Modified;

                // success !
                string str = "o";
                return RedirectToAction("Index", new { str = str });
            }

            // fail !
            return View(os);
        }

After updating an OS row using this, the row does not get updated. What's wrong with this please?

OSModel

[Table("OS")]
public class OSModel
{
    [Key]
    public int idOS { get; set; }

    [Required]
    public string nameOS { get; set; }

    [Required]
    public string versionOS { get; set; }

    [Required]
    public string editionOS { get; set; }

    [Required]
    public string servicepackOS { get; set; }

    [Required]
    public int bitsOS { get; set; }

    public OSModel(){}
}

Knowing that at the debug mode, I get the full data of the input os aside of idOS which is set to 0.

Answer 1

Thing is you must add _db.SaveChanges() after _dn.Entry(os).State=... , to save the change in the database Try this:

    [HttpPost]
    [ValidateAntiForgeryToken]
    public ActionResult Modifier(OSModel os)
    {    
        if (ModelState.IsValid)
        {

            _db.Entry(os).State = EntityState.Modified;
            _db.SaveChanges();// you must add this line
            // success !
            string str = "o";
            return RedirectToAction("Index", new { str = str });
        }

        // fail !
        return View(os);
    }