public DownList() { SetStyle( ControlStyles.UserPaint | ControlStyles.AllPaintingInWmPaint | ControlStyles.OptimizedDoubleBuffer | ControlStyles.ResizeRedraw | ControlStyles.Selectable | ControlStyles.SupportsTransparentBackColor | ControlStyles.DoubleBuffer, true); //强制分配样式重新应用到控件上 UpdateStyles(); chatVScroll = new YScroll(this); }