Simple update with Entity Framework

Question

I have the following code and I cannot achieve saving the changes. The parameter of my method is a string containing the RefCode of a product I want to modify in the database, then the query is pulling the BaseProduct that is supposed to be modified. (I tried to simplify the code and set it in English, so I have probably introduced some syntactic errors, but in my code in debug mode, I get all the info FROM the DB). Is there something wrong with the "select new" in the Linq query ?

public static void UpdateProduct(ViewProduct productToUpdate)
    {
        using (var context = new my_Entities())
        {
            var BaseProduct = (from prod in context.Product
                               where prod.Ref == productToUpdate.BaseProduct.RefPrd
                                      select new ViewBaseProduct
                                      {
                                          RefPrd = prod.Ref,
                                          DescrPrd = prod.DescrPrd,
                                          NormeCe = (bool)prod.NormeCE
                                      }).FirstOrDefault();

            if (BaseProduct != null)
            {
                //BaseProduct.NormeCe = false;
                BaseProduct = productToUpdate.BaseProduct;
                context.SaveChanges();
            }
        }
    }

Carlos Corral Carvajal · Accepted Answer · 2013-04-05 07:27:20Z

2

But BaseProduct is a ViewBaseProduct object, is ViewBaseProduct a entity class? It seems it is a ViewModel class.

You have to get de Product entity, modify his fields and savechanges. It seems you only apply changes to the ViewModel class.

Try this:

public static void UpdateProduct(ViewProduct productToUpdate)
{
    using (var context = new my_Entities())
    {
        var BaseProduct = (from prod in context.Product
                           where prod.Ref == productToUpdate.BaseProduct.RefPrd)
                          .FirstOrDefault();

        if (BaseProduct != null)
        {
            //BaseProduct.NormeCe = false;
            BaseProduct.field1 = productToUpdate.BaseProduct.field1;
            BaseProduct.field2 = productToUpdate.BaseProduct.field2;

            //update the necesary fields
            //......
            context.SaveChanges();
        }
    }
}

answered Apr 5, 2013 at 7:27

Carlos Corral Carvajal

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2 Comments

Bro Over a year ago

you are right, ViewBaseProduct is a ViewModel class. I'll try what you propose it seems so obvious now...

Bro Over a year ago

that was it :) Thanks Carlos ! When I was doing a "select new ViewBaseProduct" in my Linq query, I was creating an object that was not "linked" to the Enity, so updating that object could not affect the datas in the database.

Linus Caldwell · Accepted Answer · 2013-04-05 02:45:08Z

0

This won't work that way. You should use the CurrentValues.SetValues() method:

contexte.Entry(BaseProduct).CurrentValues.SetValues(productToUpdate.BaseProduct);

answered Apr 5, 2013 at 2:45

Linus Caldwell

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Comments

Sagar Hirapara · Accepted Answer · 2013-04-05 04:42:34Z

I think you have to Try this

public static void UpdateProduct(ViewProduct productToUpdate)
    {
        using (var contexte = new my_Entities())
        {
            var BaseProduct = (from prod in contexte.Product
                               where prod.Ref == productToUpdate.BaseProduct.RefPrd
                                      select new ViewBaseProduct
                                      {
                                          RefPrd = prod.Ref,
                                          DescrPrd = prod.DescrPrd,
                                          NormeCe = (bool)prod.NormeCE
                                      }).FirstOrDefault();

            if (BaseProduct != null)
            {
                BaseProduct.BaseProduct.RefPrd=productToUpdate.BaseProduct.RefPrd
                BaseProduct.BaseProduct.DescrPrd=productToUpdate.BaseProduct.DescrPrd
                BaseProduct.BaseProduct.NormeCE==(bool)productToUpdate.BaseProduct.NormeCE
                contexte.SaveChanges();
            }
        }
}

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