How to prevent a CView derived class from gaining the input focus

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I'm wondering how to handle an input focus event on a CView derived class before the event occurs. It's like calling a OnSettingFocus if such an event handler exists, and then cancel the input focus, to make my view never gaining the input focus (for some reasons).
NB: CWnd::EnableWindow(FALSE); wont work, because my view has a child view and the call of CWnd::EnableWindow(FALSE); will make the child view disabled also.
Help me please to do that :(

Posted 4-Apr-11 3:41am

Mr. Tomay

Updated 4-Apr-11 3:46am

v2

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Michael Melkonian · Answer 1 · 2011-04-07T14:53:00

SQL

BEGIN_MESSAGE_MAP(CSomeRecordSetView, CFormView)
    ON_COMMAND(ID_RECORD_NEXT_MM, OnRecordNextMm)
 END_MESSAGE_MAP()

C#

void CSomeRecordSetView::OnRecordNextMm()
{
    if (m_CurrentRecord < m_NumRecords - 1)
    {
        // open set
        m_pSet->Open();

        // move to the incremented record
        m_pSet->Move(++m_CurrentRecord);

        // copy data from set to view
        DataExchange(m_pSet, TRUE);

        // cause re-draw
        UpdateData(FALSE);

        // close the set
        m_pSet->Close();

    }
}

DataExchange method (you have to write this) moves data from RecordSet to View (whan argument is TRUE) and vice versa (when argument is FALSE), e.g.

C#

void CSomeRecordSetView::DataExchange(CSomeRecordSet *pSet, BOOL Direction)
{
    if (Direction)
    {
        // copy from recordSet to view
        m_SomeData = m_pSet->m_SomeData;
    }
    else
    {
        // copy from dialog to recordset
        m_pSet->m_SomeData = m_SomeData;
    }
}

This, as far as I remember, replaces the default behaviour of RecordSet view Next button. Prev, First and Last are similar.

mbue · Answer 2 · 2011-04-04T03:44:00

Solution 1

EnableWindow(0);

Thats easy. ;-)

Posted 4-Apr-11 3:44am

mbue

Comments

Mr. Tomay 4-Apr-11 9:49am

I have updated my question

mbue 4-Apr-11 9:54am

What you want to do?
* The view should not gain the focus
* But the child can get input focus?
Is this correct?
Then call SetFocus(hChild) on CYourView::OnSettingFocus().
Regards.

Mr. Tomay 4-Apr-11 10:16am

The problem is that it does'nt exist an OnSettingFocus event handler

mbue 4-Apr-11 10:32am

CWnd::OnSetFocus or handle the message WM_SETFOCUS.
Regards.

Mr. Tomay 4-Apr-11 10:42am

CWnd::OnSetFocus : The framework calls this member function after gaining the input focus. It's late here. I want to handle it before, and then cancel the operation. Is it possible ?

mbue 4-Apr-11 12:59pm

Thats impossible, because the function SetFocus(hwnd) calls directly SendMessage(hwnd,WM_SETFOCUS,...) there is no message between (so far as i know).
Regards.

Michael Melkonian 4-Apr-11 21:09pm

Is this the only view that you have?

I am guessing there is another view that you want to keep the focus at. If not, ignore the rest of my comment.

In which case, you could handle WM_KILLFOCUS in another view before it loses focus and immediately re-establish it (and hence prevent the CYourView view from getting focus).

Or even something along the lines of:
((CMainFrame*)GetParentFrame())->SetActiveView(this);

Mr. Tomay 5-Apr-11 4:05am

it could work. but it's something heavy (reactivate after deactivate). I would like to prevent activation before. I found this: http://msdn.microsoft.com/en-us/library/1f31c334.aspx
But I don't know how to do to cancel the activation.

Michael Melkonian 5-Apr-11 20:34pm

Well it is going to look heavy either way I think - you are, in effect, you are overriding what framework does when it sets the focus. To be honest, I am struggling to see why would you ever want to do that - much easier to just ignore the input even if the focus is set - if thats what your application requires.

Mr. Tomay 6-Apr-11 3:29am

Well, the purpose of all this is: When you create an SDI application with ODBC database support, the framework will create for you a toolbar with move buttons, and these move buttons will be enabled only if a CRecordView view is active. (My child view is a CRecordView, and its parent is not). So when the user would like to scroll through the recordset, he click on the appropriate move button from the main toolbar. But if my CRecordView is not the active view (for example the parent one has gained the input focus by a user click), the main toolbar move buttons will be disabled, and the user has to click in the child CRecordView just to make the main toolbar move buttons enabled and then scroll where he wants to move.

NB: My parent view has a CTabCtrl with hidden tabs which contains all the CRecordView child views. and the appropriate child CRecordView selection is done throw a task panel. So, no need to make the parent view gaining the focus.

Michael Melkonian 6-Apr-11 21:56pm

Ahh, the CRecordView. I had some trouble with OnRecordNext and OnRecordPrev too, so in one project I had to do my own handlers for the move buttons. It only had 6-8 lines and I think replicates the default framework-generated ones. Let me know if you the code I can dig it out.

Probably too much trouble if you only have (a smallish) problem with losing focus.

Have you tried handling First Last Next and Prev toolbar buttons in CMainFrame instead? Find the CRecordView and call View's handler? That way, the buttons should always be enabled.

mbue 7-Apr-11 7:22am

That sounds good. Perhaps you can offer that to the op as solution.
Regards.