Fragment Simple Help!

i just try to learn fragments so i create a fragment axml like;

`<?xml version="1.0" encoding="utf-8"?>

    <TextView xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/text_view"
    android:layout_height="match_parent"
    android:layout_width="match_parent" />  

    </FrameLayout>`

and a fragment class

` public class FragTest : Fragment { public override void OnCreate(Bundle savedInstanceState) { base.OnCreate(savedInstanceState);

}
public override View OnCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
  {
    var text = "Haluk";
    var view = inflater.Inflate(Resource.Layout.MyFragX, container, false);
    var textview = view.FindViewById<TextView>(Resource.Id.text_view);
    textview.Text = text;

    return View;
  }

}`

when i try to trig fragment my app crashes

why is that?

` var newFrag = new FragTest();

  var ft = FragmentManager.BeginTransaction();
  ft.Add(Resource.Id.fragment_container, newFrag);
  ft.Commit();`