Nope. Doesn't work

[MikeAtTheMill]

This issue tracker is for documentation

For product issues, use https://github.com/aspnet/EntityFramework/issues I followed the database first approach. I'm using VS 2019 community edition. And SQL Server & Tools 18. Don't know why it doesn't work. But SaveChanges did not persist the updates to the database. I checked the tables using SSMS w/ T-SQL selects. Nothing in either table. Sorry folks.

[roji]

@MikeAtTheMill you're going to have to provide some code to show what you're doing - it's not possible for us to help without more info beyond "SaveChanges did not persist". Please submit a minimal, runnable code sample that shows what you're trying to do.

[MikeAtTheMill]

https://learn.microsoft.com/en-us/ef/ef6/fundamentals/databinding/winforms Sorry. I just copy / paste the code in the example

using System; using System.Collections.Generic; using System.ComponentModel; using System.Data; using System.Drawing; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows.Forms; using System.Data.Entity;

namespace WinFormswithEFSample
{
    public partial class Form1 : Form
    {
        ProductContext _context;
        public Form1()
        {
            InitializeComponent();
        }

        protected override void OnLoad(EventArgs e)
        {
            base.OnLoad(e);
            _context = new ProductContext();

            // Call the Load method to get the data for the given DbSet
            // from the database.
            // The data is materialized as entities. The entities are managed by
            // the DbContext instance.
            _context.Categories.Load();

            // Bind the categoryBindingSource.DataSource to
            // all the Unchanged, Modified and Added Category objects that
            // are currently tracked by the DbContext.
            // Note that we need to call ToBindingList() on the
            // ObservableCollection<TEntity> returned by
            // the DbSet.Local property to get the BindingList<T>
            // in order to facilitate two-way binding in WinForms.
            this.categoryBindingSource.DataSource =
                _context.Categories.Local.ToBindingList();
        }

        private void categoryBindingNavigatorSaveItem_Click(object sender, EventArgs e)
        {
            this.Validate();

            // Currently, the Entity Framework doesn’t mark the entities
            // that are removed from a navigation property (in our example the Products)
            // as deleted in the context.
            // The following code uses LINQ to Objects against the Local collection
            // to find all products and marks any that do not have
            // a Category reference as deleted.
            // The ToList call is required because otherwise
            // the collection will be modified
            // by the Remove call while it is being enumerated.
            // In most other situations you can do LINQ to Objects directly
            // against the Local property without using ToList first.
            foreach (var product in _context.Products.Local.ToList())
            {
                if (product.Category == null)
                {
                    _context.Products.Remove(product);
                }
            }

            // Save the changes to the database.
            this._context.SaveChanges();

            // Refresh the controls to show the values         
            // that were generated by the database.
            this.categoryDataGridView.Refresh();
            this.productsDataGridView.Refresh();
        }

        protected override void OnClosing(CancelEventArgs e)
        {
            base.OnClosing(e);
            this._context.Dispose();
        }
    }
}

[MikeAtTheMill]

I am running the example. Then I switch to SSMS and check the tables in the database. I am NOT using the localdb - I am using a developer edition of SQL Server. I check both tables by using SELECT * FROM etc. They are empty my friend.

[MikeAtTheMill]

Hold on. The problem was in the app.config. It works. Sorry to bother you.