Using WPF, I want to know when the rendering is completed

[Leros]

I'm new to WPF. I'm doing some performance testing on different methods for drawing shapes to see which method is faster. I need to measure the time from when I issue a command to when the actual pixels appear on the screen.

WPF has a UI thread and a separate hidden Render thread. There is an OnLoaded event which is triggered when the UI thread passes the drawing off to the Render thread. But I need to know when things are actually rendered. The OnLoaded event occurs a long time before the item is actually rendered.

I've got a method where I can get fairly accurate results, but it triggers a little bit before the pixels actually show up. Its good enough, but I would like to get more accurate results.

The best method would be if I could invoke a low priority item in the Render thread. That way, once all the rendering is done, that item would execute. This would occur right after the rendering is completed. Problem is, I don't think I can access the Render thread. Does anybody know otherwise?

(I have no idea if it matters, but I'm using .Net3.5 and C#).

Cliffs:
- Using WPF
- I want to access the Render thread
- Can I?

 

[nickbits]

A couple thoughts, neither is exactly what you want but may help somewhat:

override the OnRender function
Hook onto CompositionTarget.Rendering