如何在mvc5中更新/删除上传的图片

// Controller
public ActionResult UpdateImage(int id)
{
    var image = db.Images.Find(id);
    if (Request.Files.Count > 0)
    {
        var file = Request.Files[0];
        if (file != null && file.ContentLength > 0)
        {
            string path = Path.Combine(Server.MapPath("~/Images"), file.FileName);
            file.SaveAs(path);
            image.ImagePath = "~/Images/" + file.FileName;
            db.SaveChanges();
        }
    }
    return RedirectToAction("Index");
}

// Controller
public ActionResult DeleteImage(int id)
{
    var image = db.Images.Find(id);
    if (image != null)
    {
        string path = Server.MapPath(image.ImagePath);
        if (System.IO.File.Exists(path))
        {
            System.IO.File.Delete(path);
        }
        db.Images.Remove(image);
        db.SaveChanges();
    }
    return RedirectToAction("Index");
}

// Controller
public ActionResult UpdateImage(int id)
{
    var image = db.Images.Find(id);
    if (Request.Files.Count > 0)
    {
        var file = Request.Files[0];
        if (file != null && file.ContentLength > 0)
        {
            string allowedExtensions = ".jpg,.jpeg,.png,.gif";
            if (allowedExtensions.Contains(Path.GetExtension(file.FileName).ToLower()))
            {
                string path = Path.Combine(Server.MapPath("~/Images"), file.FileName);
                file.SaveAs(path);
                image.ImagePath = "~/Images/" + file.FileName;
                db.SaveChanges();
            }
            else
            {
                ModelState.AddModelError("file", "Invalid file type.");
            }
        }
    }
    return RedirectToAction("Index");
}