You could find it in many places, for example,
http://www.winprog.org/tutorial/app_four.html[
^].
However, this topic is not extremely popular; and that's quite explainable. Here is the idea: who needs MDI, ever? Why torturing yourself and scaring off your users?
Do yourself a great favor: do not use MDI at all. You can do much easier to implement design without it, with much better quality. MDI is highly discouraged even by Microsoft, in fact, Microsoft dropped it out of WPF and will hardly support it. More importantly, you will scare off all your users if you use MDI. Just don't. Please see:
http://en.wikipedia.org/wiki/Multiple_document_interface#Disadvantages,
How to Create MDI Parent Window in WPF?.
There are not so many UI designs that are so inconvenient and cumbersome. Everyone I know (and I know very many computer people, not just developers) hate such user experience and well agree with me. You cannot find any serious company or UI developer using such design.
Instead, you can develop better UI using just on main window, not counting some small number of
modal windows. The views you put in separate MDI children (windows), could be well put in some controls withing the main window; and they controls could act much better than MDI children, giving much better user experience. Use tabbed UI, or dockable (or combined), or controlled by tree/list view TOC-page style, or folding panels or something like that.
[EDIT]
For example, to see how people develop tabbed UI, you can take a look at this CodeProject article:
Tabbed View Interface in an MFC Doc View Application[
^].
And this is some MSDN sample:
https://msdn.microsoft.com/en-us/library/bb982946%28v=vs.90%29.aspx[
^].
See also:
https://msdn.microsoft.com/en-us/library/65dtx4a4.aspx[
^].
—SA
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