label inside scrollview display outside in android

I put label in the Content so that inside th scrollview;

            string lrc = "...";//the string display in label mutililine so that it should contained in a scrollview
            var stackLayout = new ScrollView()
                {
                    HeightRequest = Device.OnPlatform(200, 300, 300) 
                    , Padding = new Thickness(10, 0, 10, 0)
                    , Content = new ContentView()
                    {
                        Content = new Label(){Text = lrc}
                    }
                };

it's fine in WinPhone and iOS, but it display outside the scrollview in android.
Example: I set scrollview a half screen, but the label too long to display all screen although label inside scrollview. It run on android platform