问Xamarin Android错误构建错误

EN

public class Screen1 : Activity
{

    private List<string> mItems;

    private ListView mListView;


    protected override void OnCreate(Bundle savedInstanceState)
    {
        base.OnCreate(savedInstanceState);

        Button clicknews = FindViewById<Button>(Resource.Id.btnlist);

        mListView = FindViewById<ListView>(Resource.Id.lstView);

        clicknews.Click += (object sender, EventArgs args) =>
        {               
            mItems = new List<string>();

            mItems.Add("Meal Plan");

            mItems.Add("Training Plan");

            ArrayAdapter<string> mAdapter = new ArrayAdapter<string>(this, 

           Android.Resource.Layout.SimpleListItem1, mItems);

           mListView.Adapter = mAdapter;

        };

        SetContentView(Resource.Layout.screen1);
    }
}