Entity Framework won't save changes in database

Question

When I try to add an item into the database, after running the app the data won't be in the database for long time memory. I don't know why, the connection is good and I already checked it many times.

 private void InsertIncomeBtn_Click(object sender, RoutedEventArgs e)
 {
     float lf = (float)Convert.ToDouble(IncomeText.Text);
     MessageBox.Show(lf.ToString());

     DateTime date = (DateTime)MovDatePick.SelectedDate;
     Movments mv1 = new Movments();
     mv1.Sum = lf;
     mv1.Date = date.Date;

     db.TotalAll.FirstOrDefault().CurrentSum += lf;
     db.Movments.Add(mv1);
     db.SaveChanges();

     IncomeWin.Close();
     MainWindow m = new MainWindow();
     m.Show();
}

I am using VS 2017 Community and writing a WPF app.

Thank for helping.

Answer 1

I'm assuming (from a lot of previous questions) that you have a SQL Server database, and your connection string most likely contains an AttachDbFileName=..... entry - correct?

If so: the whole AttachDbFileName= approach is flawed - at best! When running your app in Visual Studio, it will be copying around the .mdf file (from your App_Data directory to the output directory - typically .\\bin\\debug - where you app runs) and most likely , your INSERT works just fine - but you're just looking at the wrong .mdf file in the end!

If you want to stick with this approach, then try putting a breakpoint on the myConnection.Close() call - and then inspect the .mdf file with SQL Server Mgmt Studio Express - I'm almost certain your data is there.

The real solution in my opinion would be to

1. install SQL Server Express (and you've already done that anyway)

2. install SQL Server Management Studio Express

3. create your database in SSMS Express , give it a logical name (eg YourDatabase )

4. connect to it using its logical database name (given when you create it on the server) - and don't mess around with physical database files and user instances. In that case, your connection string would be something like:

    Data Source=.\\\\SQLEXPRESS;Database=YourDatabase;Integrated Security=True 

   and everything else is exactly the same as before...

Also see Aaron Bertrand's excellent blog post Bad habits to kick: using AttachDbFileName for more background info.