On Update command is not working for dynamically created button in MFC

Question

In my code, i have added button in view class in OnCreate(). I included On Command and On Update COmmand funtionality. Here On command fucntion is working when i click the button. But On Update COmmand is not working. Im updating the pressing status of the button using this OnUpdateCommand().

In OnCreate()

rBar.left = 580;
    rBar.right = 620;
    cBZoomOut.Create("",WS_CHILD|WS_VISIBLE|BS_BITMAP ,rBar,this,IDC_TZOOMOUT);
    cBZoomOut.SetIcon(IDI_TZOOMOUT);

    rBar.left = 625;
    rBar.right = 665;
    cBZoomin.Create("",WS_CHILD|WS_VISIBLE|BS_BITMAP ,rBar,this,IDC_TZOOMIN);
    cBZoomin.SetIcon(IDI_TZOOMIN);

Message maps for those buttons.

    afx_msg void OnUpdateTzoomout(CCmdUI *pCmdUI);
    afx_msg void OnTzoomin();
    afx_msg void OnUpdateTzoomin(CCmdUI *pCmdUI);
    afx_msg void OnTzoomout();

    ON_UPDATE_COMMAND_UI(IDC_TZOOMOUT, &CTrendView::OnUpdateTzoomout)
    ON_COMMAND(IDC_TZOOMIN, &CTrendView::OnTzoomin)
    ON_UPDATE_COMMAND_UI(IDC_TZOOMIN, &CTrendView::OnUpdateTzoomin)
    ON_COMMAND(IDC_TZOOMOUT, &CTrendView::OnTzoomout)

On command and OnUpdatecommand function:

void CTrendView::OnTzoomout()
{   
    sTimeStatus.Format("<=>%d",Minute/2);

}
void CTrendView::OnUpdateTzoomout(CCmdUI *pCmdUI)
{   
    if (Minute == 16)
        pCmdUI->Enable(FALSE);
    else
        pCmdUI->Enable(TRUE);
}

In both Zoomin and Zoomout function, OnUpdateCommnad is not working.

I loaded this inside View. I have added some controls at the end of the View not in childframe. — Anu, Jan 21 '19 at 05:59
Is `cBZoomIn` a `CButton`? In that case you have to enable/disable it manually. — Barmak Shemirani, Jan 21 '19 at 06:17
Yes, it is CButton created dynamically in OnCreate(). decalred in headerfile as CButtonST cBZoomin,cBZoomOut,; — Anu, Jan 21 '19 at 06:40
You can create a time in your `CView` class and call `cBZoomIn->EnableWindow(TRUE/FALSE)`, or override `CWinApp::OnIdle()` — Barmak Shemirani, Jan 21 '19 at 06:47

xMRi · Answer 1 · 2019-01-22T08:00:51.910

2

This routing isn't done automatically.

You have to handle WM_IDLEUPDATECMDUI. Usually you call the internal OnUpdateCmdUI virtual function. This finally calls UpdateDialogControls.

You find the details in TN021

Just set a breakpoint on a working OnUpdate Handler. And look into the call stack. Than you can see and imagine how the whole stuff works.

There is also a possible way to use WM_KICKIDLE and UpdateDialogControls. See this article.

edited Jan 22 '19 at 08:00

answered Jan 21 '19 at 09:04

xMRi

14,982
3
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`WM_IDLEUPDATECOMDUI` is not Windows or MFC message. The `OnUpdateCmdUI` routine may get called only when the associated menu item or tool button needs activation. – Barmak Shemirani Jan 21 '19 at 16:17
Please read TN024. Is is a MFC message! https://learn.microsoft.com/en-us/cpp/mfc/tn024-mfc-defined-messages-and-resources?view=vs-2017 – xMRi Jan 21 '19 at 17:23

score 1 · Answer 2 · answered Jan 21 '19 at 17:46

1

Try the following.

In TrendView.h add this:

afx_msg LRESULT OnKickIdle(WPARAM wParam, LPARAM lParam);

In TrendView.cpp add this:

#include <afxpriv.h>

...
ON_MESSAGE(WM_KICKIDLE, OnKickIdle)
...

LRESULT CTrendView::OnKickIdle(WPARAM wParam, LPARAM lParam)
{
    UpdateDialogControls(this, FALSE);
    return 0;
}

answered Jan 21 '19 at 17:46

l33t

18,692
16
103
180

I have included this in both cpp and .h file. But no change. i though by including this, OnUpdateCommandUI will get triggered. Whether it will work only on CDialog class. Because my class is CView.I added controls through coding. – Anu Jan 22 '19 at 09:46

On Update command is not working for dynamically created button in MFC

2 Answers2