public void LoadproductInfo(ComboBox comboBox1) { try { SqlDataReader rd; rd = dw.LoadProductInfo_2(); while (rd.Read()) { if ((!comboBox1.Items.Contains(rd["type"]) && (rd["type"] != ""))) { comboBox1.Items.Add(rd["type"]); } } } catch (Exception e) { MessageBox.Show(e.Message); } }