在PPT放映时， 画出来的直线屏幕一闪，又没有了,如何解决
PowerPoint.SlideShowSettings oSettings;
oSettings=Globals.ThisAddIn.Application.ActivePresentation.SlideShowSettings;
oSettings.Run();
PowerPoint.SlideShowView ssv = Globals.ThisAddIn.Application.SlideShowWindows[1].View;
if (ssv.PointerType == PowerPoint.PpSlideShowPointerType.ppSlideShowPointerPen)
{
ssv.PointerType = PowerPoint.PpSlideShowPointerType.ppSlideShowPointerArrow;
}
else
{
ssv.PointerType = PowerPoint.PpSlideShowPointerType.ppSlideShowPointerPen;
ssv.PointerColor.RGB = 123;
}
ssv.DrawLine((float)0.0, (float)0.0, (float)150.0, (float)150.0);

画出来的直线屏幕一闪，又没有了

[解决办法]
http://www.cnblogs.com/dlwang2002/archive/2007/10/29/941000.html