如何在WPF中测量屏幕渲染时间

I am attempting to measure the performance for a WPF based application. Currently we have code that times how long it takes to add the content to the WPF render tree. At this point, control is returned to our program. The problem is that there is still a lag before content is displayed on the screen by WPF. For complicated rendering trees, this can be a matter of seconds.I am attempting to measure the performance for