Form窗体添加边框阴影效果

    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        public bool DrawShadow { get; set; } = true;
        protected override CreateParams CreateParams
        {
            get
            {
                CreateParams cp = base.CreateParams;
                if (DrawShadow)
                    cp.ClassStyle |= 0x20000;
                return cp;
            }
        }


    }