dismiss is not working on single button click

Question

dismiss method is  is not working on single button click in xamarin android i have created

F FragmentTransaction transcation = FragmentManager.BeginTransaction();
Dialogclass signup = new Dialogclass();
signup.Show(transcation, "Dialog Fragment");  in main activity

then i created dialogue.cs class

  close.Click += delegate
{

Toast.MakeText(Activity, "THANKS FOR UR FEEDBACK!", ToastLength.Short).Show();
Dismiss();

}; is not working on single click