TimePickerFragment.txt

//fragment
   public class TimePickerFragment : DialogFragment,
                                    TimePickerDialog.IOnTimeSetListener
    {
        // TAG can be any string of your choice.
        public static readonly string TAG = "X:" + typeof(TimePickerFragment).Name.ToUpper();

        // Initialize this value to prevent NullReferenceExceptions.
         Action<string> _dateSelectedHandler = delegate { };

        public static TimePickerFragment NewInstance(Action<string> OnTimeSet)
        {
            TimePickerFragment frag = new TimePickerFragment();
            frag._dateSelectedHandler = OnTimeSet;
            
            return frag;
        }

        public override Dialog OnCreateDialog(Bundle savedInstanceState)
        {
            DateTime currently = DateTime.Now;
            TimePickerDialog dialog = new TimePickerDialog(Activity,this,
                currently.Hour,
                currently.Minute,
                false);
            return dialog;
        }

        public void OnTimeSet(TimePicker view, int hourOfDay, int minute)
        {
           // DateTime selectedDate = new DateTime(year, monthOfYear + 1, dayOfMonth);
            //  Log.Debug(TAG, selectedDate.ToLongDateString());
            string time = string.Format("{0}:{1}", hourOfDay, minute.ToString().PadLeft(2, '0'));

            _dateSelectedHandler(time);
        }

     
 

    }
//Call Fragment

   TimePickerFragment frag = TimePickerFragment.NewInstance(delegate (string time)
                {
                    button.Text = time ;
                });
                frag.Show(FragmentManager, TimePickerFragment.TAG);