winform中真正的透明label

winform中的透明都是假透明，只是将背景色设置为父级容器的背景色。所以从网上找到这个真正透明的label。

public partial class transparentLabel : UserControl
    {
        public transparentLabel()
        {
            InitializeComponent();
            SetStyle(ControlStyles.SupportsTransparentBackColor
              | ControlStyles.UserPaint
              | ControlStyles.AllPaintingInWmPaint
              | ControlStyles.Opaque, true);
            this.BackColor = Color.Transparent;
        }
        protected override CreateParams CreateParams
        {
            get
            {
                CreateParams cp = base.CreateParams;
                cp.ExStyle |= 0x00000020; //WS_EX_TRANSPARENT 
                return cp;
            }

        }
    }