When you create a rich edit control window using the default class name (MSFTEDIT_CLASS
), all messages are going to be sent to its parent window. Since you are not that parent window, you are not able to handle those messages.
So you will need to subclass the control, substituting your own window procedure that will be called directly, instead of allowing the messages to be passed on to the parent. That is simple to do; I've discussed it before in this answer for a regular edit control. The altered example code looks like this:
// Stores the old original window procedure for the rich edit control.
WNDPROC wpOldRichEditProc;
// The new custom window procedure for the rich edit control.
LRESULT CALLBACK CustomRichEditProc(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam)
{
switch (msg)
{
...
}
// Pass the messages you don't process on to the original window procedure.
CallWindowProc(wpOldRichEditProc, hWnd, msg, wParam, lParam);
}
And when you create the control:
// Create the rich edit control
HWND hWnd = CreateWindowEx(...)
// Subclass it.
wpOldRichEditProc= (WNDPROC)SetWindowLongPtr(hWnd,
GWLP_WNDPROC,
(WNDPROC)CustomRichEditProc);
You will also need to make sure to unsubclass the control whenever it is destroyed. The other example demonstrates doing that in response to messages received by the parent window, but that won't work in your case, since you're not getting messages for the parent window. Instead, you'll need to remove the subclass from the control in response to its own WM_NCDESTROY
message:
SetWindowLongPtr(hWnd, GWLP_WNDPROC, (LONG_PTR)wpOldRichEditProc);
Or, version 6 of the common controls library introduced a new, less error-prone method of subclassing using a set of utility functions. (The critical functionality was actually there in earlier versions, but it was undocumented.) Considering that you do not have control over the process that actually owns the window, this is arguably the preferred approach.
There is a demo of both approaches here on MSDN.
And of course, you don't have to subclass only individual controls. You can also register a custom window class that behaves the same way as the built-in rich edit control, but still gives you first crack at the messages received by windows of that class. I can't tell from the question whether that's necessary or not; it sounds like you only have a single control you care about.