How to get the id of the selected row from a table

public void DisplayRecord()
        {

            using (SqlConnection mySqlConnection = new SqlConnection(connectionString))
            {
                using (SqlCommand mySqlCommand = new SqlCommand("ReadTransactions", mySqlConnection))
                {
                    try
                    {
                        mySqlCommand.CommandType = CommandType.StoredProcedure;
                        //mySqlCommand.Connection = mySqlConnection;
                        mySqlConnection.Open();
                        using (SqlDataReader QueryReader = mySqlCommand.ExecuteReader())
                        {
                            if (QueryReader.HasRows)
                            {
                                while (QueryReader.Read())
                                {
                                    string id = QueryReader.GetString(0);
                                    string date = QueryReader.GetDateTime(1).ToString();
                                    string amount = QueryReader.GetInt32(2).ToString();
                                    string quantity = QueryReader.GetInt32(3).ToString();
                                    string edit = "";
                                    //table.Append("<table>");                                                                     
                                    data += "<tr><td>" + id + "</td><td>" + date + "</td><td>" + amount + "</td><td>" + quantity + "</td><td>" + "<button UseSubmitBehavior='False' type='button' runat='server' OnClick='edit_click'>Edit</button>" + "</td></tr>";
                                }
                            }
                            else
                            {
                                table.Append("<tr>No Record Found</tr>");
                            }
                        }
                    }
                    catch (SqlException ex)
                    {
                        Console.WriteLine(ex.Message);
                    }
                    finally
                    {
                        mySqlConnection.Close();
                    }
                    dataHolder.Text = data;
                }
            }
        }



        protected void edit_click(object sender, EventArgs e) {
            Console.WriteLine("Click Me");
            Console.Read();
            paymentBox.Text = "";
            quantityBox.Text = "dasf";
        }