For page editing in Admin's Panel to update product data Write next method for this:

[HttpPost]
        public ActionResult Edit(Product product)
        {
            if (ModelState.IsValid)
            {
                repository.SaveProduct(product);
                TempData["message"] = string.Format("{0} have been saved", product.Name);
                return RedirectToAction("Index");
            }
            else
            {
                return View(product);
            }

        }

and

public void SaveProduct(Product product)
        {
            if (product.ProductID == 0)
            {
                context.Products.Add(product);
            }
            context.SaveChanges();
        }

And this view Edit:

@model SportStore.Domain.Entities.Product

@{
    ViewBag.Title = "Admin: Edit " + @Model.Name;
    Layout = "~/Views/Shared/_AdminLayout.cshtml";
}

Edit @Model.Name

@using (Html.BeginForm())
{
    @Html.EditorForModel()
     type="submit" value = "Save" />
    @Html.ActionLink("Cancel and return to List", "Index") 
}

When i click Save data are not updated. I try debug for public ActionResult Edit(Product product) and parametr product all correct. In method public void SaveProduct(Product product) the parameter is passed also correctly