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TrackBar Snapping RRS feed

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    Hi

    Env: Win10, VC++, MFC

    I create a TrackBar (CSliderCtrl) and want snap it to each 100 step. but the result is not work and the slider is stuck or move smoothly. In the MSDN wrote the TRBN_THUMBPOSCHANGING notification result is ignored but i think is is important to snap!

    my code is:

    void CZoomCtrl::OnSliderChanging(NMHDR* pNMHDR, LRESULT* pResult)
{
	NMTRBTHUMBPOSCHANGING* pNMTR = (NMTRBTHUMBPOSCHANGING*)pNMHDR;
	*pResult = 1;

	int nPos = pNMTR->dwPos;
	
	if ((nPos % 100) == 0)
	{		
		nPos = (int)(nPos / 100) * 100;
		m_wndZoomSlider.SetPos(nPos);
		*pResult = 0;
	}
	
}

    Thanks

    Saturday, July 9, 2016 6:01 PM

Answers

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    I solved the problem. The correct code is below.

    void CZoomCtrl::OnSliderChanging(NMHDR* pNMHDR, LRESULT* pResult)
{
	NMTRBTHUMBPOSCHANGING* pNMTR = (NMTRBTHUMBPOSCHANGING*)pNMHDR;

	if (pNMTR->nReason == TB_ENDTRACK)
		return;
		
	int nPos = pNMTR->dwPos;	
	if ((nPos % 100) < 50) // do not use equal (==) here ;-)
	{		
		nPos = nPos / 100 * 100;
		m_wndZoomSlider.SetPos(nPos);
	}

	*pResult = 1;
}

    • Marked as answer by drjackool Sunday, July 10, 2016 7:50 AM
    Sunday, July 10, 2016 7:50 AM