How to send a notification that's handled by ON_NOTIFY?

Question

I'm trying to post a LVN_ ITEMCHANGED to my custom gridlist's owner. I know how to send a WM_ User message using PostMessage (as shown here)

::PostMessage( AfxGetMainWnd()->GetSafeHwnd(), WM_REFRESH, (WPARAM)pBuffer, (LPARAM)GetOutputIdx() );

When I use this same code to send a LVN_ITEMCHANGED message though,

::PostMessage( AfxGetMainWnd()->GetSafeHwnd(), LVN_ITEMCHANGED, 0, 0);

it doesn't seem to be caught by the

ON_NOTIFY(LVN_ITEMCHANGED, ..., ...) 

I have in the owner class.

Am I wrong to be using ::PostMessage to send a Notify event?
Is there a difference between Notify messages and WM_ prefix messages or how they're handled?
Can someone post a sample of how I would send the message properly?

Thanks in advance.

Edit
I found another solution to the problem. See my answer below.

Answer 1

I found out that I could override the message handler in my derived class and pass the message on to my parent control simply by using this code in the message map:

ON_NOTIFY_REFLECT_EX(LVN_ITEMCHANGED, OnListItemChanged)

Then in OnListItemChanged, I first call the base class function then return FALSE. This causes the message to be reflected to the parent class effortlessly.

Answer 2

Send WM_NOTIFY, pass control id as wParam and NMHDR* as lParam.

You'll need to allocate an NMHDR variable and fill it appropriately - set code to LVN_ITEMCHANGED and idFrom to the control id. You can only use SendMessage(), not PostMessage() since the receiving party will directly read memory through the NMHDR* pointer.

Smth like this:

NMHDR nmhdr;
nmhdr.code = LVN_ITEMCHANGED;
nmhdr.idFrom = controlId;
nmhdr.hwndFrom = controlWindowHandle;
SendMessage( targetWindowHandle, WM_NOTIFY, controlId, &nmhdr );