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Send an SMS opt-in message and detect for the presence of a keyword response from users. This is an example of an SMS Alerts system opt-in using CDYNE's SMSNotify! API from within a legacy ASP.NET WebForms application.
<form id="form1" runat="server">
<h2>Enter Your Mobile Device Number to Register</h2>
<p>CDYNE Alerts lets you receive school, organization, or community alerts over SMS.</p>
<label for="mobile">Mobile Number</label>
<input type="text" runat="server" id="mobile" class="textbox" placeholder="ex. '(555)-555-5555'" required="required" />
<label class="checkbox">
<input type="checkbox" id="checktoc" runat="server" required="required"/>
I agree to the terms & conditions.
<asp:Button ID="btnSubmit" runat="server" Text="Sign-up for CDYNE Alerts"
OnClick="btnSubmit_Click" />
<div id="success" runat="server">
You will receive a message from our system shortly. Reply "<b>YES</b>" to activate CDYNE communications.
//This is an example of how you can responsibly implement SMS messaging by verifying customer opt-ins with CDYNE's SMSNotify! API.
//API reference sheet -
public partial class signup : System.Web.UI.Page
IsmsClient client = new IsmsClient("sms2wsHttpBinding");
//Request a free license key for any CDYNE API at
Guid Key = new Guid("PUT YOUR LICENSEKEY HERE");
protected void Page_Load(object sender, EventArgs e)
//These are HTML elements on the page's front end
mobile.Disabled = false;
btnSubmit.Visible = true;
success.Visible = false;
protected void btnSubmit_Click(object sender, EventArgs e)
//Pulling customer's phone number from the text-input on page
string phoneNumber = mobile.Value;
//Setting the specifics of the API SMS Request
SMSAdvancedRequest customerOptIn = new SMSAdvancedRequest();
customerOptIn.LicenseKey = Key;
List<SMSRequest> requests = new List<SMSRequest>();
SMSRequest optIn = new SMSRequest();
optIn.Message = "CDYNE Info Alerts: Reply YES to confirm. Reply HELP for help or call 8009843710. Msg&Data rates may apply. Msg freq per acct setup. Pwr'd by CDYNE.";
//SMS Message recipient(s)
optIn.PhoneNumbers = new string[] { phoneNumber };
//Sets the dedicated number (DID) that the SMS message will be sent from. If not declared, the message will be sent from a pool of CDYNE's shared numbers
optIn.AssignedDID = "YOUR DID HERE";
//Gathering it all up
customerOptIn.SMSRequests = requests.ToArray();
//Making API call
SMSResponse[] smsResponses = client.AdvancedSMSsend(customerOptIn);
//Hiding the submit button and showing the success message.
mobile.Disabled = true;
btnSubmit.Visible = false;
success.Visible = true;
//Server-side code for the postback page
public partial class signup_postback : System.Web.UI.Page
//Global API Details that I don't want in my main code
IsmsClient client = new IsmsClient("sms2wsHttpBinding");
Guid Key = new Guid("YOUR LICENSE KEY HERE");
protected void Page_Load(object sender, EventArgs e)
//Declaring empty variables to store the details of a customer's reply message.
string SMSResponse = "";
string MessageID = "";
string MatchedMessageID = "";
string ReferenceID = "";
string FromPhoneNumber = "";
string ToPhoneNumber = "";
string ResponseReceiveDate = "";
string Message = "";
//Catching and setting the details of the reply into variables.
SMSResponse = Request.Params["SMSResponse"];
MessageID = Request.Params["MessageID"];
MatchedMessageID = Request.Params["MatchedMessageID"];
ReferenceID = Request.Params["ReferenceID"];
FromPhoneNumber = Request.Params["FromPhoneNumber"];
ToPhoneNumber = Request.Params["ToPhoneNumber"];
ResponseReceiveDate = Request.Params["ResponseReceiveDate"];
Message = Request.Params["Message"];
//Checking that the customer is confirming their Opt-in with keyword "yes".
if (Message.ToLower() == "yes")
//Now you might add the customer's phone number to your records/db
//Make the API request to send out the final confirmation/welcome message out to the customer
SMSAdvancedRequest confirmation = new SMSAdvancedRequest();
//Getting API Key from variable that was declared earlier
confirmation.LicenseKey = Key;
List<SMSRequest> requests = new List<SMSRequest>();
SMSRequest confirmationMessage = new SMSRequest();
confirmationMessage.Message = "Welcome to CDYNE Info Alerts. Reply 'STOP' to cancel. Reply HELP for help or call 8009843710. Msg&Data rates may apply. Msg freq per acct setup. Pwr'd by CDYNE.";
//The confirmation/welcome message will go to the number that is opting-in.
confirmationMessage.PhoneNumbers = new string[] { FromPhoneNumber };
confirmationMessage.AssignedDID = "YOUR DID HERE";
//Gather up all the details of the request
confirmation.SMSRequests = requests.ToArray();
//Send out the confirmation/welcome
SMSResponse[] smsResponses = client.AdvancedSMSsend(confirmation);
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