不能通过嵌套类型X访问外部类型X的非静态成员

我想在Main Activity中调用一个方法来使用
调用一个新的Fragment((FragmentActivity)活动)。ShowFragment(新SmokeSensor ());

抛出错误:

不能访问外部类型

的非静态成员

Android.Support.V4.App。

'*******. Fragments.Dashboard.ViewAdapter '

我做错了什么?

代码:

public void ShowFragment(SupportFragment fragment) {
    var transaction = SupportFragmentManager.BeginTransaction();
    connectionStatus.Visibility = ViewStates.Gone;
    if (!ConnectionDetector.IsConnected(this)) {
        connectionStatus.Visibility = ViewStates.Visible;
        transaction.Detach(currentFragment);
        transaction.Commit();
        drawerLayout.CloseDrawer(leftDrawer);
        return;
    }
    if (fragment == currentFragment) {
        transaction.Detach(currentFragment);
        transaction.Attach(currentFragment);
        transaction.Commit();
        drawerLayout.CloseDrawer(leftDrawer);
        return;
    }
    transaction.SetCustomAnimations(Resource.Animation.slide_in,
                                    Resource.Animation.slide_out);
    transaction.Replace(Resource.Id.fragment_container, fragment);
    transaction.Commit();
    drawerLayout.CloseDrawer(leftDrawer);
    currentFragment = fragment;
}