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From: Xanthus on 20 Mar 2005 16:17
I have a CDateTimeCtrl on my dialog. It is valid to leave this blank (no
entry) so I want to be able to allow this.
I have added the FORMAT event handler for formatting it to the empty string
if the underlying COleDateTime is 0.0, or the short date.

I also added the FORMATQUERY handler to try to allow no input. This is
causing problems when I try to select a date.
I set the string and max length for the string to "", " / / ", etc to
match the FORMAT, but when I do the GetWindowText(csEffDate), it always
comes back as "0xee0xee..."

Can the CDateTimeCtrl handle the empty string as input?

Here is the code:


void CEditProductDlg::OnDtnFormatDatetimepickerEqdate(NMHDR *pNMHDR, LRESULT
*pResult)
{
LPNMDATETIMEFORMAT pDTFormat = reinterpret_cast<LPNMDATETIMEFORMAT>(pNMHDR);
// TODO: Add your control notification handler code here
COleDateTime odtEQDate;
m_dtEQDate.GetTime(odtEQDate);

if(odtEQDate.m_dt == 0.0)
{
pDTFormat->pszDisplay = m_csEQDateFmtd;
}
else
{
pDTFormat->pszDisplay = odtEQDate.Format("%d/%m/%Y");
}

*pResult = 0;
}

void CEditProductDlg::OnDtnFormatqueryDatetimepickerEqdate(NMHDR *pNMHDR,
LRESULT *pResult)
{
LPNMDATETIMEFORMATQUERY pDTFmtQuery =
reinterpret_cast<LPNMDATETIMEFORMATQUERY>(pNMHDR);

CDC* pDC;
CFont* pFont;
CFont* pOrigFont;
COleDateTime odtEQDate;

// get the control value as COleDateTime
// this is coming back as 0.0 as expected
m_dtEQDate.GetTime(odtEQDate);

// Prepare the device context for the GetTextExtentPoint32 call.
pDC= GetDC();

pFont= GetFont();
if(!pFont)
pFont->CreateStockObject(DEFAULT_GUI_FONT);


pOrigFont = pDC->SelectObject(pFont);

// Check to see if this is the callback segment desired. If so,
// use the longest text segment to determine the maximum
// width of the callback field, and then place the information into
// the NMDATETIMEFORMATQUERY structure.

// Only FORMATQUERY we are using so we know what it is
//if(!lstrcmp("X",pDTFmtQuery->pszFormat))

if(odtEQDate.m_dt == 0.0)
{
//m_csEQDateFmtd = _T(" / / ");
m_csEQDateFmtd = _T("");
::GetTextExtentPoint32 (pDC->m_hDC,
m_csEQDateFmtd.GetString(),m_csEQDateFmtd.GetLength(), &(pDTFmtQuery->szMax));
}
else
{
m_csEQDateFmtd = _T("00/00/0000");
::GetTextExtentPoint32 (pDC->m_hDC,
m_csEQDateFmtd.GetString(),m_csEQDateFmtd.GetLength(), &(pDTFmtQuery->szMax));
}


// Reset the font in the device context then release the context.
pDC->SelectObject(pOrigFont);
ReleaseDC(pDC);

*pResult = 0;
}

//
// OnChange
//
void CEditProductDlg::OnDtnDatetimechangeEQDate(NMHDR *pNMHDR, LRESULT
*pResult)
{
LPNMDATETIMECHANGE pDTChange = reinterpret_cast<LPNMDATETIMECHANGE>(pNMHDR);

*pResult = 0;

if(m_blnInitted)
{
CString csEQDate;
COleDateTime odtEQDate;

// Is this valid? Has window text been moved
here yet?
m_dtEQDate.GetTime(odtEQDate);

// GetWindowText to compare to odtEQDate
m_dtEQDate.GetWindowText(csEQDate);
csEQDate.Trim();
// This is always coming back as
// "0xee0xee..."
// and as invalid
// Why?
odtEQDate.ParseDateTime(csEQDate,VAR_DATEVALUEONLY);
if(odtEQDate.GetStatus() == COleDateTime::valid)
{
}
}

Thanks,

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