Context不包含FragmentManager的定义

Question

我得到了abvove错误，为什么？我在适配器中使用它，它不能通过属性Activity.FragmentManager.BeginTransaction给我活动。我将上下文传递给构造函数并且我得到了错误。

Button buttonAddExercise = row.FindViewById<Button>(Resource.Id.buttonAddExercise);
buttonAddExercise.Click += delegate {
    FragmentTransaction transaction = myContext.FragmentManager.BeginTransaction();
};

public DayObject(Context context, List<Fragments.Day> items) {
    myItems = items;
    myContext = context;
}