Question

In my ASP.NET web-based application, I have a normal ASP.NET button that has a method behind it for sending emails as following:

ASP.NET Code:

<asp:Button ID="btnSendReminders" runat="server" Text="Send Reminders" OnClick="btnSendReminders_Click"  />

Code-Behind:

protected void btnSendReminders_Click(object sender, EventArgs e)
        {
            SendEmailTOAllUser();
        }


        protected void SendEmail(string toAddresses, string fromAddress, string MailSubject, string MessageBody, bool isBodyHtml)
        {
            SmtpClient sc = new SmtpClient("Mail Server");
            try
            {
                MailMessage msg = new MailMessage();
                msg.From = new MailAddress("[e-mail]", "PMOD Safety Services Portal (PSSP)");

                // In case the mail system doesn't like no to recipients. This could be removed
                //msg.To.Add("[e-mail]");

                msg.Bcc.Add(toAddresses);
                msg.Subject = MailSubject;
                msg.Body = MessageBody;
                msg.IsBodyHtml = isBodyHtml;
                sc.Send(msg);
            }
            catch (Exception ex)
            {
                throw ex;
            }

        }

        protected void SendEmailTOAllUser()
        {
            string connString = "Data Source=localhost\\sqlexpress;Initial Catalog=psspForTest;Integrated Security=True";

            using (SqlConnection conn = new SqlConnection(connString))
            {
                var sbEmailAddresses = new System.Text.StringBuilder(2000);
                string quizid = "";

                // Open DB connection.
                conn.Open();

                string cmdText = "SELECT MAX (QuizID) As mQuizID FROM dbo.QUIZ WHERE IsSent <> 0";
                using (SqlCommand cmd = new SqlCommand(cmdText, conn))
                {
                    SqlDataReader reader = cmd.ExecuteReader();
                    if (reader != null)
                    {
                        while (reader.Read())
                        {
                            // There is only 1 column, so just retrieve it using the ordinal position
                            quizid = reader["mQuizID"].ToString();

                        }
                    }
                    reader.Close();
                }

                string cmdText2 = @"SELECT e.Username, d.DivisionShortcut
                                FROM
                                  employee e
                                  join Divisions d on (e.DivisionCode = d.SapCode)
                                  left join 
                                    (select A.QuizID, a.Username 
                                     from UserQuiz a join 
                                     (select max(QuizID) QuizID from dbo.Quiz where IsSent=1) b
                                     on a.QuizId = b.QuizID
                                     ) c
                                   on e.Username = c.Username
                                 WHERE c.QuizID is null
                                 Order By d.DivisionShortcut";
                using (SqlCommand cmd = new SqlCommand(cmdText2, conn))
                {
                    SqlDataReader reader = cmd.ExecuteReader();
                    if (reader != null)
                    {
                        while (reader.Read())
                        {
                            var sName = reader.GetString(0);
                            if (!string.IsNullOrEmpty(sName))
                            {
                                if (sbEmailAddresses.Length != 0)
                                {
                                    sbEmailAddresses.Append(",");
                                }
                                // Just use the ordinal position for the user name since there is only 1 column
                                sbEmailAddresses.Append(sName).Append("@DomainServer.com");
                            }
                        }
                    }
                    reader.Close();


                    // Add the parameter to the command
                    var oParameter = cmd.Parameters.Add("@QuizID", SqlDbType.Int);


                    var sEMailAddresses = sbEmailAddresses.ToString();
                    string link = "<a href='http://StartQuiz.aspx?testid=" + quizid + "'> Click here to participate </a>";
                    string body = @"<font color='red' size='18pt'><b> ***REMINDER*** </b></font> <br /><br /> 
                                Good day, <br /><br />
                                <b>This is just a gentle reminder asking you to participate in the last new short safety quiz </b>"
                                    + link +
                                    @"<br /><br />
                                Also, give yourself a chance to gain more safety culture by reading the PMOD Newsletter.
                                <br /><br /><br />
                                PLEASE <span class='highlight'>IGNORE</span> THIS MESSAGE IF YOU HAVE ALREADY PARTICIPATED IN THIS QUIZ.
                                <br /> <br /><br /> <br />
                                This email was generated using the <a href='http://pmv/pssp/Default.aspx'>Safety Portal (PSSP) </a>. 
                                Please do not reply to this email.";

                    int sendCount = 0;
                    List<string> addressList = new List<string>(sEMailAddresses.Split(','));
                    StringBuilder addressesToSend = new StringBuilder();

                    for (int userIndex = 0; userIndex < addressList.Count; userIndex++)
                    {
                        sendCount++;
                        if (addressesToSend.Length > 0)
                            addressesToSend.Append(",");

                        addressesToSend.Append(addressList[userIndex]);
                        if (sendCount == 10 || userIndex == addressList.Count - 1)
                        {
                            SendEmail(addressesToSend.ToString(), "", "REMINDER: Notification of New Weekly Safety Quiz", body, true);
                            addressesToSend.Clear();
                            sendCount = 0;
                        }
                    }


                    // Update the parameter for the current quiz
                    oParameter.Value = quizid;
                    // And execute the command
                    cmd.ExecuteNonQuery();

                }
                conn.Close();
            }
        }

Now, instead of using <asp:Button>, I want to use:

 <ajaxToolkit:ConfirmButtonExtender ID="btnSendReminders" runat="server" TargetControlID="btnSendReminders"
                                                ConfirmText="Are you sure you want to click this?"
                                                OnClientCancel="CancelClick" />

to have a ConfirmMessage. But I don’t know why I got the following error:
**

Extender control ‘btnSendReminders’ cannot extend ‘btnSendReminders’.
Extender controls of type ‘AjaxControlToolkit.ConfirmButtonExtender’
cannot extend controls of type
‘AjaxControlToolkit.ConfirmButtonExtender’.

And I don’t know why. So how can I use it instead of the <asp:button>?

UPDATE:

I just figured out how to use it. I should use it as following:

<asp:Button ID="btnSendReminders" runat="server" Text="Send Reminders" OnClick="btnSendReminders_Click"  />
            <ajaxToolkit:ConfirmButtonExtender ID="ConfirmButtonExtender1" runat="server" TargetControlID="btnSendReminders"
                                                ConfirmText="Are you sure you want to send reminders to these employees?"
                                                OnClientCancel="CancelClick">
                                                </ajaxToolkit:ConfirmButtonExtender>

But the problem now is when the confirm message appears, and click on the Cancel button, still the page will be refreshed and the reminders will be sent. How to prevent that in case of clicking the Cancel button?

Answer 1

Use following code Confirm button ajax extender to get confirm box:

  <asp:Button ID="btnSendReminders" runat="server" Text="Send Reminders" OnClick="btnSendReminders_Click"  />
<ajaxToolkit:ConfirmButtonExtender ID="cbe" runat="server"
   TargetControlID="btnSendReminders"
    ConfirmText="Are you sure you want to Send Reminders?"
    />