public void RetrieveProductPrice(String ID) { SqlConnection RetrieveProductPrice = new SqlConnection("Data Source=SELAKA\\SELA;Initial Catalog=SATHOSA;Integrated Security=True"); SqlCommand Select = new SqlCommand("Select Product_Selling_Price FROM Product Where Product_ID=@ID;", RetrieveProductPrice); //MessageBox.Show(""+ID); Select.Parameters.AddWithValue("@ID", ID); try { SqlDataReader DataReader2; RetrieveProductPrice.Open(); DataReader2 = Select.ExecuteReader(); while (DataReader2.Read()) { metroTextBox7.Text = DataReader2["Product_Selling_Price"].ToString(); } DataReader2.Close(); } catch (Exception ex) { MessageBox.Show("" + ex); } finally { RetrieveProductPrice.Close(); } }