Focus Problem in MFC Dialog Project

Hi everyone,

I've created a dialog project to implement a simple calculator. I'm trying to set the focus to be on my dialog so I will be able to use the WM_KEYDOWN to capture keyboard input. I've enabled the ON_WM_SETFOCUS() and ON_WM_KILLFOCUS() options so I will know when my dialog gets the focus, and when then focus is taken away from it.

I've tried setting the focus using SetFocus() in the following way:


BOOL CMyCalculatorDlg::OnInitDialog()

{

CDialog::OnInitDialog();

// Set the icon for this dialog. The framework does this automatically

// when the application's main window is not a dialog

SetIcon(m_hIcon, TRUE); // Set big icon

SetIcon(m_hIcon, FALSE); // Set small icon


CWnd::SetFocus();


return FALSE; // return TRUE unless you set the focus to a control

}



However, when debugging the program I see that the focus is indeed given to the dialog at first ( ON_WM_SETFOCUS() is activated), but then the focus is immediately taken away from it ( ON_WM_KILLFOCUS() is activated ), and because of this the dialog doesn't respond to key pressings.

What am I doing wrong?

BTW: I'm using visual studio 2005 with an MFC project.

Thanks alot!

Maybe this?

return FALSE; // return TRUE unless you set the focus to a control

Put it back to TRUE and see what is happening

No, it was TRUE to begin with, the behavior stays the same.

I understood that returning FALSE tells the dialog manager (I'm not sure that's the name of it) that the focus was set to the current dialog, but I'm not sure.

Look, If you have made the dialog and select it that dialog have a focus, then press some key on the keyboard, message will be dispatched to your dialog.
You need to have OnKeyDown event handled:

OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags)

then you just handle nChar-s to call appropriate functions:
if( nChar == '1' ) {
Pressed(1);
}

if( nChar == VK_RETURN ) {
Calculate();
}

etc...

You don't need to bother with focus not focus problem.

I've already added the use of OnKeyDown. I press the keyboard upon startup of the dialog but this function is never entered. That what made me suspect the focus issue from the first place.
Then I added the OnSetFocus and OnKillFocus to try and take a deeper look into this issue, and I saw that the dialog does get the focus on startup (OnSetFocus is entered), but is then stripped away from it (OnKillFocus is entered).

Quote:

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Originally Posted by Ido_I

I've already added the use of OnKeyDown. I press the keyboard upon startup of the dialog but this function is never entered. That what made me suspect the focus issue from the first place.
Then I added the OnSetFocus and OnKillFocus to try and take a deeper look into this issue, and I saw that the dialog does get the focus on startup (OnSetFocus is entered), but is then stripped away from it (OnKillFocus is entered).

---

we need to understand what is the exact behavior that you are after and what part of that is not working.

ok, let's try putting it this way:

I build a calculator (using MFC) that is implemented using a dialog box that contains a menu, buttons and an edit control. I would like the dialog box to control the keyboard input from one main place. The way I understand it, if I use OnKeyDown in the main dialog file (XXDlg.cpp), then every input of the keyboard should direct me to the OnKeyDown routine, where I can handle the input the way I like it.

But that is not the behavior I get. Instead, after running the project, if I press the keyboard then nothing happens (OnKeyDown() is never entered).

I know I'm doing something wrong, as my knowledge of the MFC is very poor, I just don't know what it is :)

Thanks.

Do you use wizard to add handlers to your dialog class?

you should have these things:

declaration in header file:
afx_msg void OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags);

message map:
ON_WM_KEYDOWN()

and function body:

void CMyDialog::OnKeyDown(UINT nChar, UINT nRepCnt, UINT nFlags)
{
// add stuff here
CDialog::OnKeyDown(nChar, nRepCnt, nFlags);
}

Quote:

---

Originally Posted by Ido_I

I've enabled the ON_WM_SETFOCUS() and ON_WM_KILLFOCUS() options so

---

Correction: you did not enable anything. You have inserted WM_SETFOCUS and WM_KILLFOCUS handlers.

[QUOTE= I'm trying to set the focus to be on my dialog so I will be able to use the WM_KEYDOWN to capture keyboard input. . .
What am I doing wrong?

BTW: I'm using visual studio 2005 with an MFC project.[/QUOTE]

Quote:

---

Originally Posted by Ido_I

I would like the dialog box to control the keyboard input from one main place. The way I understand it, if I use OnKeyDown in the main dialog file (XXDlg.cpp), then every input of the keyboard should direct me to the OnKeyDown routine,

---

Quote:

---

Originally Posted by Ido_I

I know I'm doing something wrong, as my knowledge of the MFC is very poor,

---

It does not matter what version of VS you are using. Also, this is not MFC. It is a dialog default behavior that you are struggling against. By design, dialog that has at least one control, never has a keyboard focus.

Quote:

---

Originally Posted by Ido_I

I know I'm doing something wrong, as my knowledge of the MFC is very poor,

---

Proper way is to insert handlers for each control. Alternatively, you can use OnNotify or OnCommand if controls generate command or notification messages.

I'm getting a little confused now - I'm trying all these advises but none is working. Let's start from the top:

Let's leave the calculator aside. Suppose I've just created a totaly new MFC Application project called "Test". The project is created with the "OK" and "Cancel" buttons. I didn't touch anything yet.

The question is simple - what are the steps I have to do (after creating the "Test" project from scratch) in-order to capture the keyboard input, when I start from this point?


From all the comments I understand it should be simple, and eventually comes down to adding the WM_KEYDOWN event handler. But I add it and insert a breakpoint inside CTestDlg::OnKeyDown.
But when I run this project, this breakpoint is never reached, meaning CTestDlg::OnKeyDown is never entered.

so again, starting from scratch after creating the project, what are the steps I need to do?

Quote:

---

Originally Posted by Ido_I

I'm getting a little confused now - I'm trying all these advises but none is working.
....
From all the comments I understand it should be simple, and eventually comes down to adding the WM_KEYDOWN event handler. But I add it and insert a breakpoint inside CTestDlg::OnKeyDown.
But when I run this project, this breakpoint is never reached, meaning CTestDlg::OnKeyDown is never entered.

so again, starting from scratch after creating the project, what are the steps I need to do?

---

I wonder, do you ever read the answers? :confused:
JohnCz has just written you very clear:

Quote:

---

Originally Posted by JohnCz

It does not matter what version of VS you are using. Also, this is not MFC. It is a dialog default behavior that you are struggling against. By design, dialog that has at least one control, never has a keyboard focus.
Proper way is to insert handlers for each control. Alternatively, you can use OnNotify or OnCommand if controls generate command or notification messages.

---

you could also try to override PreTranslateMessage method and handle WM_KEYDOWN there, although, it is not the best way and should be usually avoided, unless your actions on the pressed keys were the same independent on the control currently having focus.

I read the answers alright, there's no need to offend or to attack. As someone who was introduced to the whole OOP concept literaly just a few days ago, I can only hope that the OOP veterans here can understand that trevial things to them might be very intrevial to me.

My actions on the pressed keys are the same, independent on the control currently having focus, so I'll try and see what PreTranslateMessage means and try this direction.

Quote:

---

Originally Posted by JohnCz

Proper way is to insert handlers for each control. Alternatively, you can use OnNotify or OnCommand if controls generate command or notification messages.

---

If I still want to do it straight-forward by inserting handlers, I can still the following handlers are available for each button control:
BCN_HOTITEMCHANGE, BN_CLICKED, BN_DOUBLECLICKED, BN_KILLFOCUS, BN_SETFOCUS and NM_THEMECHANGED.

How is any of these handlers related to keyboard input control?

The problem is solved using the PreTranslateMessage, thanks for all who bothered to help!

It will still be nice to get an answer on my last question though...

Quote:

---

Originally Posted by Ido_I

If I still want to do it straight-forward by inserting handlers, I can still the following handlers are available for each button control:
BCN_HOTITEMCHANGE, BN_CLICKED, BN_DOUBLECLICKED, BN_KILLFOCUS, BN_SETFOCUS and NM_THEMECHANGED.

How is any of these handlers related to keyboard input control?

---

None of them. They all are just notification messages :cool:
You should subclass your controls and handle this message in the derived classes.

OK, now it all makes sense!!

Many thanks!

Quote:

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Originally Posted by Ido_I

I read the answers alright, there's no need to offend or to attack. As someone who was introduced to the whole OOP concept literaly just a few days ago,

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Good luck. Nevertheless question you have is not related to OOP paradigm. It is related to Windows programming.

Quote:

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Originally Posted by Ido_I

How is any of these handlers related to keyboard input control?

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They are not handlers. As Victor pointed they are notification codes, used in a WM_COMMAND message when button is pressed using either mouse or (having focus) enter or a space bar.