문자열 저장,불러오기 함수

        protected string retrieveset(string name)
        {
            //retreive 
            var prefs = Application.Context.GetSharedPreferences("MyApp", FileCreationMode.Private);              
            var somePref = prefs.GetString(name, null);

            //Show a toast
            //RunOnUiThread(() => Toast.MakeText(this, somePref, ToastLength.Long).Show());
            return somePref;
        }
        protected void saveset(string name,string val1){

            //store
            var prefs = Application.Context.GetSharedPreferences("MyApp", FileCreationMode.Private);
            var prefEditor = prefs.Edit();
            prefEditor.PutString(name,val1);
            prefEditor.Commit();
        }