Grab another window by handle and show it as a preview/video in my form (C#)

So basically I am trying to capture the o开发者_JAVA技巧utput of a render window that is hidden by default to put into a controller application as a preview. I've been told by some people in my line of work that this is possible by grabbing the window handle and somehow putting that as a video on your existing form. But I have no clue how to do that currently (outside of getting the handle itself)

Been looking all morning and a bit yesterday and haven't found exactly what I need yet.

Trying to do this in C#

This can be done via the WinAPI SetParent call. See my answer to a similar question here.