自动生成的代码CreateInstance方法，GComponent转化无效

public class LoginView : Window

{

    private LoginFrame _frame;



    protected override void OnInit()

    {

        base.OnInit();

        this.contentPane = LoginFrame.CreateInstance();

        _frame = this.contentPane as LoginFrame;

        _frame.MakeFullScreen();

        this.Center();

    }

}

namespace Login

{

    public partial class LoginFrame : GComponent

    {

        public GImage BG;

        public GButton EnterGameBtn;

        public const string URL = "ui://kgt6ib3v10p1q4";



        public static LoginFrame CreateInstance()

        {

            return (LoginFrame)UIPackage.CreateObject("Login", "LoginFrame");//提示转化失败

        }



        public override void ConstructFromXML(XML xml)

        {

            base.ConstructFromXML(xml);



            BG = (GImage)GetChildAt(0);

            EnterGameBtn = (GButton)GetChildAt(1);

        }

    }

}