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ON_UPDATE_COMMAND_UI vs ON_COMMAND

Posted on 2010-11-12
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Last Modified: 2012-05-10
Previously in MFC I've managed to use the ON_UPDATE_COMMAND_UI handler to set the state of check boxes and buttons on application menu bars and let ON_COMMAND set the new state.

I'm now using a ribbon bar with a CBCGPRibbonSlider on it. The position of the slider maintained by ON_UPDATE.. and a change to the position from the ON_COMMAND handler.

THE PROBLEM is in the ON_COMMAND handler I use pCtrl->GetPos(); only to find that the ON_UPDATE_COMMAND_UI has already set it back to the previous position.

I could ignore the GetPos value but have no other CBCGPRibbonSlider method to know its new position.

Am I going about the UPDATE + COMMAND interface the wrong way or should the CBCGPRibbonSlider return the position better?

void CMainFrame::OnMapDDIDetails()
{
	int iDDIViewDetails = -1;
	CBCGPRibbonSlider* pCtrl  = (CBCGPRibbonSlider*)m_wndRibbonBar.FindByID(IDC_MAP_DDI_DETAILS, FALSE);
	if(pCtrl!=NULL)
	{
		iDDIViewDetails = pCtrl->GetPos();
		if((iDDIViewDetails>=0)||(iDDIViewDetails<=2))
			ChangeDetails(iDDIViewDetails);
	}
}
void CMainFrame::OnUpdateMapDDIDetails(CCmdUI* pCmdUI)
{
	int iDDIViewDetails = -1;
	CBCGPRibbonSlider* pCtrl  = (CBCGPRibbonSlider*)m_wndRibbonBar.FindByID(IDC_MAP_DDI_DETAILS, FALSE);
	if(pCtrl!=NULL)
	{
		iDDIViewDetails = GetDetailState();
		if((iDDIViewDetails>=0)||(iDDIViewDetails<=2))
			pCtrl->SetPos(iDDIViewDetails);
	}
}

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Question by:itdeptneci
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3 Comments
 
LVL 31

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Zoppo earned 500 total points
ID: 34119674
Hi itdeptneci,

the only way to avoid this is to simply not set the control's position within the ON_UPDATE_COMMAND_UI handler. The ON_UPDATE_COMMAND_UI handler is used to implement the visible state of a GUI element's, it's not intended to be used to update data which might be associated with that control. And IMO this is really senseful, since if one uses a ON_COMMAND_UPDATE_UI handler to change any data may initiate another ON_UPDATE_COMMAND_UI.

So, I would suggest you add a 'int' member to your applications document - in 'OnMapDDIDetails' you can retrieve its value as you now do for 'iDDIViewDetails'. In 'OnUpdateMapDDIDetails' just handle visibility/disabled-state of the control. Add a 'OnActivateView' handler and use the 'SetPos' there as you before did in 'OnUpdateMapDDIDetails'.

Hope that helps,

ZOPPO
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LVL 40

Expert Comment

by:evilrix
ID: 34824134
This question has been classified as abandoned and is being closed as part of the Cleanup Program. See my comment at the end of the question for more details.
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