VsPackage - how to use winform control instead of Default WPF control in VS2019?

Question

use thisi code in VS2010 is valid,but in VS2019 is invalid, why?

 public MyToolWindow() :  base(null)  
        {  
            this.Caption = Resources.ToolWindowTitle;  
            this.BitmapResourceID = 301;  
            this.BitmapIndex = 1;  
            control = new MyControl();  
        }  
   
        override public IWin32Window Window  
        {  
            get  
            {  
                return (IWin32Window)control;  
            }  
        }