How to check if Vertical Scrollbar in CListBox

Question

3.86/5 (3 votes)

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Hey,

is there a way to check if the vertical scrollbar is visible in a CListBox.
I've tried this solution but it doesen't seem to work:

C++

if(GetLBox().GetStyle() & WS_VSCROLL)
{
    // some Actions here
}

Thanks a lot for quick answers :)

Posted 16-Jan-14 23:31pm

olid4

Updated 28-Jan-14 20:47pm

v5

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3 solutions

Solution 3

When there's no better way, I think this is the best way to solve the problem:

if(rectListBox.Height() > GetLBox().GetCount() *  GetLBox().GetItemHeight(0))

There may be some problems with borders and stuff like that. But IMHO this should work appropriate in most cases.

Posted 19-Jan-14 21:28pm

olid4

Updated 19-Jan-14 21:33pm

v3

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CBadger · Accepted Answer · 2014-01-16T23:53:00

Solution 1

Try this

C++

bool bHScroll = (m_List.GetStyle()&WS_HSCROLL)!=0;
bool bVScroll = (m_List.GetStyle()&WS_VSCROLL)!=0;

// if not answer look at source :-)

source[+]

Posted 16-Jan-14 23:53pm

CBadger

Comments

olid4 17-Jan-14 7:20am

Sorry, I didn't mean CListCtrl. Instead I need the corresponding function for a CListBox.

Jochen Arndt · Accepted Answer · 2014-01-17T01:06:00

Solution 2

You may use GetScrollBarInfo()[^]:

C++

bool bVisible = false;
SCROLLBARINFO SbVert;
SbVert.cbSize = sizeof(SbVert);
if (GetLBox().GetScrollBarInfo(OBJID_VSCROLL, &SbVert))
{
    // Index 0 of rgstate is the scrollbar itself
    // See SCROLLBARINFO in the MSDN
    if (0 == sbi.rgstate[0] & (STATE_SYSTEM_INVISIBLE | STATE_SYSTEM_UNAVAILABLE))
        bVisible = true;
}

[UPDATE]
For windows that did not have the WS_VSCROLL style set upon creation, the GetScrollBarCtrl()[^] function may be used:

C++

bool bVisible = false;
CWnd *pScrollWnd = GetLBox()->GetScrollBarCtrl(SB_VERT);
if (pScrollWnd && pScrollWnd->IsKindOf(RUNTIME_CLASS(CScrollBar)))
{
    if (pScrollWnd->IsWindowVisible())
        bVisible = true;
}

Posted 17-Jan-14 1:06am

Jochen Arndt

Updated 17-Jan-14 1:36am

v2

Comments

olid4 17-Jan-14 7:20am

Sorry, I didn't mean CListCtrl. Instead I need the corresponding function for a CListBox.

Jochen Arndt 17-Jan-14 7:25am

Than you should update your question (use the green 'Improve question' link) so that others know it.

Have you tried my code?
I'm not sure but it may also work with CListBox.

Has your list box the WS_VSCROLL style set?
If not, you can use GetScrollBarCtrl(). I will update my answer with an example.

olid4 17-Jan-14 7:29am

I updated my question.
I will try to work with GetScrollBarCtrl().

Jochen Arndt 17-Jan-14 7:39am

Yes, but you forgot to update the title (which I checked when wroting my comment).

olid4 17-Jan-14 7:55am

Sorry again!
=> Updated!

olid4 17-Jan-14 7:59am

Your updated Code always sais false in my case, because GetScrollBarCtrl returns always 0x00.

Jochen Arndt 17-Jan-14 8:06am

As I wrote: That code works only for windows that did not have the WS_VSCROLL bit set.

But GetScrollBarInfo() should also work with CListBox (according to http://forums.codeguru.com/showthread.php?422845-ScrollBar-Presence-in-ListBox&p=1571820#post1571820). If so check also the rgstate[0] value. It may have different flags set.

olid4 17-Jan-14 8:54am

BOOL HasVertScrollbar() const
{
bool bVisible = false;

if( GetLBox().GetStyle() & WS_VSCROLL )
{
SCROLLBARINFO sbInfo;
sbInfo.cbSize = sizeof( SCROLLBARINFO );

if( GetLBox().GetScrollBarInfo( OBJID_VSCROLL, &sbInfo ) )
{
// Index 0 = Scrollbar
if( ( sbInfo.rgstate[0] & ( STATE_SYSTEM_INVISIBLE | STATE_SYSTEM_UNAVAILABLE ) ) == 0 )
{
bVisible = true;
}
}
}
else
{
CWnd* pScrollWnd = GetLBox().GetScrollBarCtrl( SB_VERT );

if( pScrollWnd && pScrollWnd->IsKindOf( RUNTIME_CLASS( CScrollBar ) ) )
{
if( pScrollWnd->IsWindowVisible() )
{
bVisible = true;
}
}
}

return bVisible;
}

returns always that a scrollbar is visible even when there's no scrollbar visible

Jochen Arndt 17-Jan-14 9:23am

Hmm. I have used GetScrollBarInfo() with a CListCtrl where it works. Did you read the complete CodeGuru thread from my previous comment? The problem has been solved there by comparing the client rect height with item height multiplied by item count.

olid4 20-Jan-14 1:57am

Yes, I have already tried this once and it worked quite well. But I thought there could be a better and easier way, because this isn't very precisely:

return !(Rect.Height() > GetCount() * GetItemHeight(0) + (CBI.rcButton.bottom - CBI.rcButton.top) + 4);