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.

cdyne_smsnotify_optin.aspx

<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" />

    <p>
        <label class="checkbox">
            <input type="checkbox" id="checktoc" runat="server" required="required"/>
            I agree to the terms & conditions.
        </label>
    </p>

    <div>
        <asp:Button ID="btnSubmit" runat="server" Text="Sign-up for CDYNE Alerts"
        OnClick="btnSubmit_Click" />

        <div id="success" runat="server">
            <span>SUCCESS!</span>
            You will receive a message from our system shortly. Reply "<b>YES</b>" to activate CDYNE communications.
        </div>
    </div>

</form>

cdyne_smsnotify_optin.cs

//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 - http://www.cdyne.com/downloads/SPECS_SMS-Notify2.pdf

    public partial class signup : System.Web.UI.Page
    {
        //API DETAILS
        IsmsClient client = new IsmsClient("sms2wsHttpBinding");

        //Request a free license key for any CDYNE API at http://www.cdyne.com/developers/trial-key
        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";

            optIn.StatusPostBackURL = "YOUR POSTBACK PAGE URL HERE";
            requests.Add(optIn);

            //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;


        }
           
        }

    

cdyne_smsnotify_postback_page.cs

//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";
                requests.Add(confirmationMessage);

                //Gather up all the details of the request
                confirmation.SMSRequests = requests.ToArray();

                //Send out the confirmation/welcome
                SMSResponse[] smsResponses = client.AdvancedSMSsend(confirmation);
            }
        }
    }