Send SMS with more than 160 characters using Xamarin.Android

Question

I tried the code mentioned in the accepted answer for Send SMS with more than 160 characters

This doesn't work as expected and no text messages are sent after I tap 'Ok' in the display alert message. I couldn't find any error, not sure what happens in the background. I don't have enough reputation to comment on this.

void TestButton_Click (object sender, System.EventArgs e)
        {
            string message = editTextTx.Text;            

            if (((decimal)message.Length/ 160) == message.Length / 160)
                text_i = message.Length / 160;
            else
                text_i = (message.Length / 160) + 1;

            Android.App.AlertDialog.Builder dialog = new Android.App.AlertDialog.Builder(this);
            Android.App.AlertDialog alert = dialog.Create();
            alert.SetTitle("Warning");
            alert.SetMessage("It will need " + text_i.ToString() + " text message(s)");
            alert.SetButton("OK", (c, ev) =>
            {

                var destinationAdd = "**MY NUMBER**";

                SmsManager sm = SmsManager.Default;
                if (message.Length >= 160)
                {
                    List<string> parts = new List<string>();
                    //split the message into parts of 160 chars.
                    var enumerable = Enumerable.Range(0, message.Length / 160).Select(i => message.Substring(i * 160, 160));
                    parts = enumerable.ToList();
                    sm.SendMultipartTextMessage(destinationAdd, null, parts, null, null);
                }
                else
                {
                    sm.SendTextMessage(destinationAdd, null, message, null, null);
                }


            });
            alert.Show();
           
        }

It works fine for one text message which has less than 160 characters with the below code:

 try
                {

                SmsManager.Default.SendTextMessage("**MY NUMBER**", null, "test message", null, null);
                }
                catch (Exception ex)
                {                    

                    Console.WriteLine(ex.Message);
                }

Answer 1

• Changed characters for breaking the messages into parts from 160 to 150 (Not sure why it doesn't work for anything between 153-160)

Thanks Jason for the help

• In the above code it was missing the last few characters because if you break the string in to parts there can be last part with less chars and not exactly 150. Changed the code and added a try and catch statement to get the all the characters in different parts

void TestButton_Click (object sender, System.EventArgs e)
        {
            string message = editTextTx.Text;            

            if (((decimal)message.Length/ 150) == message.Length / 150)
                text_i = message.Length / 150;
            else
                text_i = (message.Length / 150) + 1;

            Android.App.AlertDialog.Builder dialog = new Android.App.AlertDialog.Builder(this);
            Android.App.AlertDialog alert = dialog.Create();
            alert.SetTitle("Warning");
            alert.SetMessage("It will need " + text_i.ToString() + " text message(s)");
            alert.SetButton("OK", (c, ev) =>
            {
var destinationAdd = "MY NUMBER";

                SmsManager sm = SmsManager.Default;
                if (message.Length >= 150)
                {
                    

                    //split the message into parts of 150 chars.

                    
                    List<string> parts = new List<string>();

                    foreach (int i in Enumerable.Range(0, text_i))
                    {
                        string tword = "";
                        try
                        {
                            tword = message[(i * 150)..][..150];

                        }

                        catch (Exception ex) //to get the last few characters
                        {
                            tword = message[(i * 150)..];
                        }
                        parts.Add(tword);                 
                                                

                    };

                    sm.SendMultipartTextMessage(destinationAdd, null, parts, null, null);
                }
                else
                {
                    sm.SendTextMessage(destinationAdd, null, message, null, null);
                }
});
            alert.Show();
           
        }