Question

We have a series of dialogs in our application for which the dialog template defines 4 buttons along the bottom of the screen. However (depending which version of our hardware the application is running on) we sometimes create 2 additional buttons and then line up the 6 buttons (4 from the template, 2 created by calling CButton::Create()) along the bottom.

The problem I have is that usually the user can move the focus between these buttons using the left / right arrow keys (there is no mouse or touchscreen, just a restricted keyboard). This follows the control TAB-order as you would expect for the 4 buttons from the template. However the 2 dynamically create controls appear to be inserted at the beginning of the TAB-order, and that means (because they are put at the right-hand side of the screen) that they are in the “wrong” order as far as the cursor keys goes. In other words, when the focus gets to the left-hand button (TAB order 1) pressing the left arrow jumps the focus to the button on the right-hand side, which is just plain confusing…

There appears to be some link between Z-order (which I can affect with SetWindowPos()) and TAB-order but it does not seem to be a simple 1-to-1: by changing the Z-order I can move the sequence around so that the buttons are completely in the wrong order, so I can change the Z-order, but I can’t work out how to get them in the right order.

Can anyone give a concise explanation of how TAB-order works, and how to control the sequencing of controls at runtime?

Edit:
kol suggested below using SetWindowPos() to set the Z-order. This I had tried before but it does not let the cursor keys control the focus as expected.

However, by rigging this up so I can use TAB (as a test — this isn’t practical for the end-user solution) I find that kol’s solution does resolve the TAB-order. The problem I have is that this is not the same as the order used by the cursor keys!

So, revised question: how can I specify the order in which left / right cursor keys move focus between controls?

Solution:
With assistance from kol and MarkRansom’s input, I have got this working now.

I used SetWindowPos() as suggested by kol to put my new buttons after the existing buttons in the TAB order, and then (as Mark suggested) made the first button WS_GROUP | WS_TABSTOP but cleared those flags from the other buttons.

However this was not enough to solve the problem, with the 2 new buttons still appearing to come before the first rather than after the second when using arrow keys (not TAB) to move around.

I looked at my dialog template, and it was like this:

IDD_QUERY DIALOG  0, 0, 156, 34
STYLE DS_SETFONT | WS_POPUP | WS_CAPTION
FONT 8, "MS Sans Serif"
BEGIN
    PUSHBUTTON      "+++Skey1+++",IDC_SKEY_1,1,21,36,12
    PUSHBUTTON      "+++Skey2+++",IDC_SKEY_2,40,21,37,12
    PUSHBUTTON      "+++Skey3+++",IDC_SKEY_3,79,21,36,12
    PUSHBUTTON      "+++Skey4+++",IDC_SKEY_4,118,21,36,12
    LTEXT           "Static",IDC_QUERY_MSG,2,1,153,15
END

So the static IDC_QUERY_MSG, which is used to display information to the user, was coming after the 4th button in the template. To resolve the problem, I moved IDC_QUERY_MSG before the first button (IDC_SKEY_1): this means the 6 buttons are not split up by a static inbetween, and has solved the problem.

Thanks to everyone for their assistance!

Answer 1

Use the SetWindowPos member of your buttons. Calling it on button A and setting its first parameter to button B, puts button A after button B in the TAB order. If you want to set the order of two controls, you have to know the controls before and after them in the TAB order – this example shows how to do this (its not MFC but pure WinAPI, but it’s easy to understand).

== UPDATE ==

I created a dialog template with four buttons at the bottom and an editbox at the top, with TAB order button1 -> button2 -> button3 -> button4 -> editbox -> button1 -> ... In OnInitDialog, I added two additional buttons at runtime, and inserted them into the existing TAB order between button4 and editbox using SetWindowPos and GetNextWindow. Pressing TAB repeatedly shows that the TAB order is correct: button1 -> button2 -> button3 -> button4 -> button5 -> button6 -> editbox -> button1 -> ...

class CTestDlg : public CDialogEx
{
public:
    CTestDlg() : CDialogEx(CTestDlg::IDD) {}
    enum { IDD = IDD_TESTDIALOG };

protected:
    CButton button5;
    CButton button6;
    virtual BOOL OnInitDialog();
};

BOOL CTestDlg::OnInitDialog()
{
    CDialogEx::OnInitDialog();

    CButton* button4 = (CButton*)GetDlgItem(IDBUTTON4);
    CWnd* next = button4->GetNextWindow(GW_HWNDNEXT);

    button5.Create("Button5", WS_CHILD|WS_VISIBLE|WS_TABSTOP|BS_PUSHBUTTON, CRect(340, 172, 415, 195), this, 1005);
    button5.SetWindowPos(button4, 0, 0, 0, 0, SWP_NOMOVE|SWP_NOSIZE); 

    button6.Create("Button6", WS_CHILD|WS_VISIBLE|WS_TABSTOP|BS_PUSHBUTTON, CRect(422, 172, 497, 195), this, 1006);
    button6.SetWindowPos(&button5, 0, 0, 0, 0, SWP_NOMOVE|SWP_NOSIZE); 

    if (next != NULL)
        next->SetWindowPos(&button6, 0, 0, 0, 0, SWP_NOMOVE|SWP_NOSIZE); 

    return TRUE;
}

void CDynamicMfcButtonTestApp::OnTestRun()
{
    CTestDlg testDlg;
    testDlg.DoModal();  
}

== UPDATE2 ==

The order of controls can be set using SetWindowPos and GetNextWindow, as above. The “tab order” and the “arrow order” can be set by setting the WS_TABSTOP and WS_GROUP styles of the controls:

• The WS_TABSTOP style specifies the controls to which the user can
  move by pressing the TAB key or SHIFT+TAB keys.

• The WS_GROUP style
  marks the beginning of a group of controls. If a control in the group
  has the input focus when the user begins pressing direction keys, the
  focus remains in the group. In general, the first control in a group
  must have the WS_GROUP style and all other controls in the group must
  not have this style. All controls in the group must be
  contiguous—that is, they must have been created consecutively with no
  intervening controls.

More details can be found on MSDN, here.