private void btnprijs_Click(object sender, RoutedEventArgs e)
		{

				decimal decprijs = Convert.ToDecimal(tbprijs.Text);

				pricehistory prijs = new pricehistory();
				prijs.price = decprijs;

				prijs.productId = (int)cmbprijs.SelectedValue;

				prijs.startdate = Convert.ToDateTime(datestart.Text);
				prijs.enddate = Convert.ToDateTime(dateend.Text);

				cmbtypeprijs.SelectedItem = null;
				cmbprijs.SelectedItem = null;
				tbprijs.Clear();
				datestart.SelectedDate.Equals("");
				dateend.SelectedDate.Equals("");

				db.pricehistories.InsertOnSubmit(prijs);
				db.SubmitChanges();
				dataprijs.ItemsSource = db.pricehistories.ToList();

				MessageBox.Show("De prijs is aangepast", "Melding!",
				MessageBoxButton.OK,
				MessageBoxImage.Information);
		}