public IActionResult EditMaterial(long matId, string Op, long productId)
        {
            if (!ModelState.IsValid)
            {
                return(RedirectToAction(nameof(Edit), new { id = productId }));
            }
            if (matId == 0 || productId == 0)
            {
                TempData["EditMessage"] = "Select a material";
                return(RedirectToAction(nameof(Edit), new { id = productId }));
            }
            if (Op == "Delete")
            {
                _workshopRepository.DeleteMaterialFromProduct(productId, matId);
                return(RedirectToAction(nameof(Edit), new { id = productId }));
            }

            ProductMaterial model = _workshopRepository.GetPMByTwoId(productId, matId);

            return(View(nameof(EditProductMaterial), model));
        }