void _PaintByD2D(Rectangle refreshArea) { D2DGraphics d2dGraphics = (D2DGraphics)graphics; if (drawType == DrawType.NOIMAGE) { WindowRenderTarget wRT = (WindowRenderTarget)d2dGraphics.RenderTarget; WindowState wstate = wRT.CheckWindowState(); if (wstate != WindowState.Occluded) { _RenderByD2D(d2dGraphics, refreshArea); } } else { _RenderByD2D(d2dGraphics, refreshArea); } }