Re: About OnSetFocus - Subnote

"Nobody" <>
Fri, 13 Jul 2007 12:29:37 -0700
Hi Joe,

Just a warning: trying to change focus from within a =

SetFocus/KillFocus handler has

problems. Years ago, it used to just lock up the app.

I can understand why KillFocus(). would cause it.
And OnSetFocus() is really just a hack. It really shouldn't be done =

SetFocus() and OnKillFocus() just let you know when the focus is being =
set to the Window, or when it is leaving it.
I was following this
But, now I see how it works and I have removed OnSetFocus() and =
OnKillFocus() in my control and added SetFocus()
to OnMouseActivate(). Which makes sense and seems to be the correct way.

I changed the view to do the same thing almost.
I'd even bet that in a Dialog somewhere it is doing the same thing that =
I am doing in my view.

"Joseph M. Newcomer" <> wrote in message =

Just a warning: trying to change focus from within a =

SetFocus/KillFocus handler has

problems. Years ago, it used to just lock up the app.
On Fri, 13 Jul 2007 01:04:42 -0700, "Nobody" <> wrote:

Hi Dave,

I knew commenting out
CView::OnMouseActivate(pDesktopWnd, nHitTest, message);
was going to be bad.

So, to remedy that.
int CMyView::OnMouseActivate(CWnd* pDesktopWnd, UINT nHitTest, UINT =


  CWnd* pWnd = GetFocus(); //Save Current Focus
  int ret = CView::OnMouseActivate(pDesktopWnd, nHitTest, message);
  pWnd->SetFocus(); //Restore it
  return ret;

I suppose I could have done it the easy way.
void CMyView::OnSetFocus()
But, at least I know what is going on now anyways.
And, if I have multiple controls in a View, like that of a Dialog, it =

will work just like a Dialog, but without the tab support.

"Nobody" <> wrote in message =


Hi David,

I get it now.

It really doesn't matter if you do SetFocus() inside a control in =


Somebody else could be doing SomethingElse()->SetFocus() afterwards, =

which takes the focus away.

I ended up removing OnSetFocus() and OnKillFocus() and the SetFocus() =

in OnInit()

I added this to get it to work correctly.
int CControl::OnMouseActivate(CWnd* pDesktopWnd, UINT nHitTest, UINT =


   // When Control becomes active, get the focus. Makes sense.
   return CWnd::OnMouseActivate(pDesktopWnd, nHitTest, message);

Think of it this way. When you tab to controls in a dialog, you would =

think the dialog manager

sets the focus to the next tabbed control, which I suppose is does, =

since it was working correctly.

But, what happens when a control is clicked instead of tabbing? It =

didn't work.

So, Tabbing works, but not if the control is clicked. That was the =

reasoning behind adding OnMouseActivate()

I was also having a problem in the View.
As soon as the Control gets the focus, it was immediately taken away.
Thats probably because when the Control becomes active, it makes the =

View active, which in turn takes away the focus.

So, what I did was this
int CMyView::OnMouseActivate(CWnd* pDesktopWnd, UINT nHitTest, UINT =


  // return CView::OnMouseActivate(pDesktopWnd, nHitTest, message);
  return TRUE;
That is what I was looking for. This is the function that makes a =

window active.

Sure enough. down inside of CView::OnMouseActive() it has
     HWND hWndFocus ::SetFocus().
*Note that it could be dangerous to just comment out =

CView::OnMouseActivate() I will probably have to move CView stuff to =
here and just remove ::SetFocus.

I am not having any problems as of yet.

So, that is actually how it works!

Also, in a dialog, I was getting that "Bonk" sound.
I actually don't need the WM_KEYDOWN messages and I just use =

PreTranslateMessage instead.

  If(pMsg->message == WM_KEYDOWN)
     UINT nChar = (UINT)pMsg->wParam;
     UINT nRepCnt = (UINT)pMsg->lParam & 0xFF00;
     UINT nFlags = (UINT)pMsg->lParam >> 16;
     OnKeyDown(nChar, nRepCnt, nFlags);
     return TRUE; //No further processing needed. No "Bonk" sound.
  return CWnd::PreTranslateMessage()

More about controls. If interested.

Dialog Initialization is different from Control.Create()
OnCreate() is not called when used in a Dialog.
Which is messing me up somewhat.

It has to do with embedding Custom Controls in a dialog.
A window is automatically created for you.
That way, you don't need to set the Rect Coodinates. It is done =


Second, I am not getting the WM_INITDIALOG messages, so I have to =

intialize the control manually

BOOL CDlgTest::OnInitDialog()
   //I shouldn't have to be doing it this way.

Back to the Drawing board, err make that Keyboard.

"Nobody" <> wrote in message =


Hi David,

Your probably right. I haven't gotten to that point just yet.
Like I said, I have not tested it in a Dialog.

The odd thing is that if I don't comment out the =


The messages go directly to the View.

The control has the "Focus", (Need a different word) but the =

WM_KEYDOWN messages are going to the View.

I'm not sure what makes a window "Active", or if it even cares.
I think it is just another rect and somewhere in the background, it =

does something like

IsTopLevelWindow() Yes
PointInRect(point) Yes,
Well then, send mouse messages to that Window.

I don't know exactly what is going on just yet.
I can open a dialog, or any other window and whatever window/control =

gains the focus.

and when I come back to my control, it has focus.
(Note that I do not call set focus again. I only call SetFocus once.)
So, that wouldn't be right if it works like your thinking, which =

sounds correct, I might add.

Maybe it is working like OnMouseMove().
If somehow, WM_MOUSEMOVE is disabled, the control would never get the =

mouse messages.

(That could be very well be the case in a static text control, hence =

the SS_NOTIFY ... for keyboard messages )

but, you don't have to call SetFocus() for mouse messages, yet the =

mouse messages still work in other windows,

That could be very well what is going on.
I could just be enabling Keyboard messages to go to my control instead =

of SetCapture() which keeps the messages

from propagating, which is what you and I are thinking.
That is the best I can figure so far.

I'll put the control in a dialog and let you know how things go.

Heck, I am happy I got this far.

Something interesting as far as controls go.
Do you know who sends WM_INITDIALOG or WM_INITIALUPDATE.
That is kind of bugging me. CFrameWnd::OnInitialUpdate() might be =

doing it for the View, but I am not sure

who sends the message to the dialog?

P.S.S. Some beer speak. Rambling on...

"David Ching" <> wrote in message =


I'm still not sure if it is correct behavior for a control to set =

focus to

itself on creation. What if the caller doesn't want that? What if =


are 2 or more instances of the control in the dialog; which one =

should get

focus? The caller (i.e. dialog) needs to have control of this! The =


would be a mess if all the controls in the dialog tried to grab =

focus like

-- David
"Nobody" <> wrote in message
I had to comment out the CWnd::OnKillFocus(). I guess that prevents =

if from

losing focus.
like it shows here
#include <afxpriv.h> //for WM_INITs
/* If in a dialog */
/* If in a view */
Control::InitialUpdate(WPARAM wParam, LPARAM lParam)
void Control::OnKillFocus(CWnd* pNewWnd)
// CWnd::OnKillFocus(pNewWnd);
I haven't tested it in a dialog yet.
Thanks all!

Joseph M. Newcomer [MVP]
MVP Tips:

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