private void btnIzmijeniTrening_Click(object sender, EventArgs e)
        {
            FrmDodajIzmijeniTrening forma = new FrmDodajIzmijeniTrening(treningBindingSource.Current as Trening);

            this.Hide();
            forma.ShowDialog();
            this.Show();
            DohvatiSveTreninge();
        }
        private void btnNoviTrening_Click(object sender, EventArgs e)
        {
            FrmDodajIzmijeniTrening forma = new FrmDodajIzmijeniTrening();

            this.Hide();
            forma.ShowDialog();
            this.Show();
            DohvatiSveTreninge();
        }