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Hi, in the past, you’ve instructed me to use the __EGCS_NO_INPLACE_CONTROL style to make my CExtGridCellComboBox subclasses act like a droplist control. Overall, it does function like a droplist, *however*, one of the nicest things about a true droplist is that you can make the list appear by clicking on the cell itself, instead of the "down arrow" button. Can you tell me how to modify the behavior of this class to act like this, or is it impossible because the NO_INPLACE_CONTROL style throws out mouse clicks in the cell’s editable area?

Create a CExtGridCell-derived class and override the CExtGridCell::OnClick() virtual method in this way:

bool CExtGridCell::OnClick(
    CExtGridWnd & wndGrid,
    const CExtGridHitTestInfo & htInfo,
    UINT nChar,
    UINT nRepCnt,
    UINT nFlags
    )
{
    ASSERT_VALID( this );
    if( nChar == VK_LBUTTON && ( nRepCnt == 1 || nRepCnt == 2 ) )
    {
        if( (nFlags&(MK_SHIFT|MK_CONTROL)) == 0 )
        {
            CExtGridHitTestInfo htInfoTrack( htInfo );
            htInfo.m_dwAreaFlags |= __EGBWA_CELL_BUTTON;
            htInfoTrack.m_nButtonType = (int)__EBTT_DROPDOWN;
            return
                wndGrid.OnGridTrackCellButton(
                    this,
                    htInfoTrack
                    );
        }
    }
    return
        CExtGridCell::OnClick(
            wndGrid,
            htInfo,
            nChar,
            nRepCnt,
            nFlags
            );
}

That should implement the behavior that is expected.

Doesn’t work -- seems that OnClick is not a virtual method in the CExtGridCellComboBox class. It is for CExtGridCell and CExtGridCellHyperlink... but the combobox isn’t derived in any way from either of those two classes.

Here is a ready-to-use CExtGridCellDropDownComboBox class:

CLASS DECLARATION:

/////////////////////////////////////////////////////////////////////////////
// CExtGridCellDropDownComboBox
 
class CExtGridCellDropDownComboBox : public CExtGridCellComboBox
{
public:
    DECLARE_SERIAL( CExtGridCellDropDownComboBox );
    IMPLEMENT_ExtGridCell_Clone( CExtGridCellDropDownComboBox, CExtGridCellComboBox );
    CExtGridCellDropDownComboBox(
        CExtGridDataProvider * pDataProvider = NULL
        );
    virtual bool OnClick(
        CExtGridWnd & wndGrid,
        const CExtGridHitTestInfo & htInfo,
        UINT nChar,
        UINT nRepCnt,
        UINT nFlags
        );
}; // class CExtGridCellDropDownComboBox

CLASS IMPLEMENTATION:

IMPLEMENT_SERIAL( CExtGridCellDropDownComboBox, CExtGridCellComboBox, VERSIONABLE_SCHEMA|1 );
 
#ifdef _DEBUG
#define new DEBUG_NEW
#undef THIS_FILE
static char THIS_FILE[] = __FILE__;
#endif
 
/////////////////////////////////////////////////////////////////////////////
// CExtGridCellDropDownComboBox
 
CExtGridCellDropDownComboBox::CExtGridCellDropDownComboBox(
    CExtGridDataProvider * pDataProvider // = NULL
    )
    : CExtGridCellComboBox( pDataProvider )
{
}
 
bool CExtGridCellDropDownComboBox::OnClick(
    CExtGridWnd & wndGrid,
    const CExtGridHitTestInfo & htInfo,
    UINT nChar,
    UINT nRepCnt,
    UINT nFlags
    )
{
    ASSERT_VALID( this );
    ASSERT_VALID( (&wndGrid) );
    ASSERT( ! htInfo.IsHoverEmpty() );
    ASSERT( htInfo.IsValidRect() );
    ASSERT( nChar == VK_LBUTTON || nChar == VK_RBUTTON || nChar == VK_MBUTTON );
    ASSERT( 0 <= nRepCnt && nRepCnt <= 3 );
    if( nChar == VK_LBUTTON && ( nRepCnt == 1 || nRepCnt == 2 ) )
    {
        if( (nFlags&(MK_SHIFT|MK_CONTROL)) == 0 )
        {
            CExtGridHitTestInfo htInfoTrack( htInfo );
            htInfoTrack.m_dwAreaFlags |= __EGBWA_CELL_BUTTON;
            htInfoTrack.m_nButtonType = (int)__EBTT_DROPDOWN;
            return
                wndGrid.OnGridTrackCellButton(
                    this,
                    htInfoTrack
                    );
        }
    }
    return
        CExtGridCellComboBox::OnClick(
            wndGrid,
            htInfo,
            nChar,
            nRepCnt,
            nFlags
            );
}