private void comboBox1_SelectedIndexChanged(object sender, EventArgs e) { ComboBox cb = sender as ComboBox; if ((cb != null) && (cb.Items.Count > 0)) { if (Bitmap) { try { // Switch the selected frame bitmap.SelectActiveFrame(cb.SelectedIndex); ReplaceBitmap(bitmap); } catch (ArgumentOutOfRangeException) { MessageBox.Show("Error changing frame.", "Error"); } } } }