detecting if a Element in a panel is visible or outside of the view

I have one canvas Element (Screen Space - Overlay) which contains several panels. Each Panel contains a ListView element.

Because gameObject.Find can't find inactive Objects I made a workaround and instead of deactivate my panel I just move it outside of the camera view when I "close" it. When I activate it then I move it to the middle of the screen at 0,0,0

So far everything works fine but now I need to detect if my Panel is viewable right now or not. The easy way is:

Code (CSharp):

1. if (transform.parent.transform.localPosition.x == 0 && transform.parent.transform.localPosition.y == 0 && transform.parent.transform.localPosition.z == 0)
2. {
3.   // is visible
4. }
5. else
6. {
7.   // is not visible
8. }

But now my problem: I want to allow drag and drop of the ui dialog and then I need to know if my panel is within the viewable area or if it was moved aways because it was "closed"

How Can I calculate the viewable edges from the camera when the center of the screen is 0,0,0?

 

I think you might be looking to calculate the camera's frustum planes. This is the documentation http://docs.unity3d.com/ScriptReference/GeometryUtility.CalculateFrustumPlanes.html

 

might be simpler to just not use Find and enable/disable as needed... why do you think you need to use find to access the panel?

 

I need the find because some dynamical game objects are created during runtime and need access to the panel