TryUpdateModel忽略GridView的Visible =“ false”列中的属性

Question

So I have my UpdateMethod here:

public void gvProducts_UpdateItem(Int32 ProductID)
{
    ProductListModel model = new ProductListModel();

    Product product = db.Products.Find(ProductID);

    if (product == null)
    {
        // MAF: The item wasn't found
        ModelState.AddModelError("", String.Format("Item with id {0} was not found", ProductID));
        return;
    }

    TryUpdateModel(model);

    if (ModelState.IsValid)
    {
        Mapper.Map(model, product);
        db.SaveChanges();
        gvProducts.EditIndex = -1;
    }
}

It's using AutoMapper to map from a Model for the ProductList page across to the Product Entity. There are a lot of columns on the GridView so we're showing and hiding some based on user selections. The issue I'm having is that any properties bound to a Visible="false" column are not being set during TryUpdateModel() and are thus populated with the defaults. This means that for example if the user doesn't have price details visible, their price gets set to 0 when they save.

Answer 1

So it turns out that the solution is in fact quite simple if somewhat more expensive for the database.

We fetch the related entities needed to remap the model from the current database values, once we have our model from the current DB values, we can then perform the update on that model which will leave the Visible="false" columns unchanged from their DB values.

We then map the model back to the entity and persist this back to the DB as per before.

public void gvProducts_UpdateItem(Int32 ProductID)
{
    Product product = db.Products
                        .Include(it => it.TaxRate)
                        .Include(it => it.Category)
                        .Include(it => it.Brand)
                        .Include(it => it.Supplier)
                        .Include(it => it.Colour)
                        .FirstOrDefault(it => it.ProductID == ProductID);

    if (product == null)
    {
        ModelState.AddModelError("", String.Format("Item with id {0} was not found", ProductID));
        return;
    }

    ProductListModel model = Mapper.Map<ProductListModel>(product);

    TryUpdateModel(model);

    if (ModelState.IsValid)
    {
        Mapper.Map(model, product);
        db.SaveChanges();
        gvProducts.EditIndex = -1;
    }
}

Hope this helps someone else.