Question

I am just got madness for getting this for updating the table related with category table and product table …but i dint success in doing that …

I have these tables

               product product_id
                       product_name 
                       product_description
                       product_price
                       product_image


              category  category_id
                        catgory_name
                        category_desc

I have done like this for updating table ….using entity framework …

    private void btnSave_Click(object sender, EventArgs e)
    {

        if (lblHiddenmode.Text == "Edit")
        {
            using (var dbcontext = new TsgEntities())
            {
                pictureBox1.Enabled = true;
                pictureBox1.Visible = true;
                Image image = pictureBox1.Image;
                byte[] bit = null;

                bit = imageToByteArray(image);
                product1 pd = new product1();

                string category = cbcategorytypes.Text;
                string categorydesc = tbCategoryDescription.Text;

                var c = new category { category_Name = category, category_Description = categorydesc };

                pd.product_Name = tbProductName.Text;
                decimal price = Convert.ToDecimal(tbProductPrice.Text);
                pd.product_Price = price;
                pd.product_Description = tbProductdescription.Text;
                pd.product_Image = bit;
                pd.category = c;                    
                dbcontext.SaveChanges();                 
                this.Close();
            }
        }

  }

NOTE: I am updating the product name which one has the product_id is 4 and category_id = 4

but it will shows at this statement pd.category = c; i got product_id = “0” and category_id = “0”

am i doing wrong when updating the table with category table .. is there any problem with update statement

Answer 1

Your code above will produce insert, not an update. In order to perform an update, you first need to retrieve a product1 instance from your context.

I don’t know what your context looks like, so I can’t post the exact code, but it will be something like this:

product1 pd = dbcontext.protucts.Where(p => p.productid == 4 
                                         && p.categoryid == 4).First();

You can then make your changes and call dbcontext.SaveChanges() and it should update your record.