problem with saving data from DataGrid to Base

Question

Hi people, I try to set up a control button functionality to save the entry data to the database. I wrote the code in C# and when I try to use it I get no errors, but thay wont to save the data. Here is the code i hope that someone will halp me.

And finally the code:

private void btnSnimi_Click(object sender, EventArgs e)
        {
            this.korisnikBindingSource.EndEdit();
            //this.BindingContext[dsAB1, "stud"].EndCurrentEdit();
            if (this.katvDataSet1.HasChanges()/*this.dsAB1.HasChanges()*/)
            {
                try
                {
                    if (konekcija.State == ConnectionState.Closed) { konekcija.Open(); MessageBox.Show("otvorena konekcija"); }
                    korisnikTableAdapter.Update(katvDataSet1.korisnik);
                    //sqlDAStud.Update(dsAB1, "stud");
                    MessageBox.Show("Snimljene sve izmjene!");
                }
                catch (System.Exception eSnimi)
                {
                    MessageBox.Show("GRESKA: " + eSnimi.Message);
                }
                finally
                {
                    konekcija.Close();
                }

            }
            else
            {
                MessageBox.Show("Nema promjena za snimanje!");
            }
        }