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How and from where are you adding items to the list control?
Mark
Mark Salsbery
Microsoft MVP - Visual C++
![Java | [Coffee]](https://codeproject.global.ssl.fastly.net/script/Forums/Images/coffee.gif)
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I'm getting my list of items (CStrings) from doing a database SELECT, then as I loop through each of the results, for a normal list control I would have inserted each item directly into the list control in OnInitDialog(), now for virtual I'm just putting those items into a list at that point, and then pointing the virtual list control to my list, calling .SetItemCount() to set the size for the list control, making the control LVS_OWNERDATA style, etc., following the tutorial in the link below:
http://www.codeproject.com/KB/list/virtuallist.aspx[^]
My OnGetDispInfo() function is pretty simple and looks like this:
void MyDlg::OnGetDispInfo(NMHDR* pNMHDR, LRESULT* pResult)
{
LV_DISPINFO* pDispInfo = (LV_DISPINFO*)pNMHDR;
LV_ITEM* pItem= &(pDispInfo)->item;
int itemid = pItem->iItem;
if (pItem->mask & LVIF_TEXT) //valid text buffer?
{
CString text = MyList_.at(itemid);
lstrcpyn(pItem->pszText, text, pItem->cchTextMax);
} // if
*pResult = 0;
}
I don't know if this is typical, but I also had problems in general with programmatically selecting an item in the virtual list control. SetItemState() didn't seem to work at all. (I should mention that I am forced to use Visual C++ 5.0, so I don't know if this could be an old problem that no longer exists). But I did see someone else had this same problem, and suggested a fake mouse click on the item. (See section 'Selection Problems' in the article below)
http://www.ddj.com/184404349;jsessionid=BVQZXGZXOGLUSQSNDLOSKH0CJUNN2JVN?_requestid=130370[^]
So I followed exactly what this guy did, and in general it seems to work great, (even though it doesn't feel like the best solution).
The only issue is with that initial selection when the list first displays. Maybe if SetItemState() worked properly, it wouldn't be an issue. Maybe it's because I'm having to simulate that mouse-click, and there's not really anything there to click on yet.
I'm not really sure.
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AmVal wrote: then pointing the virtual list control to my list, calling .SetItemCount() to set the size for the list control
Cool thanks!
You should be using SetItemCountEx() instead of SetItemCount() on a virtual list
(ListView_SetItemCountEx() is the Win32 equivalent).
Right after that call would be the place to select an item I would think.
You shouldn't have to simulate a mouse click...
Are you sure the selection isn't sticking just because the control doesn't have focus?
Where are you calling SetItemCount() from?
What does your SetItemState() code look like?
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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From OnInitDialog(), I am calling my BuildList() function to get the data from the database and load into my list. As soon as I finish loading the list, I call SetItemCount(). (I don't know if this ancient version I'm using has SetItemCountEx(). I tried using it, but I got a compile error that 'SetItemCountEx' is not a memeber of CListCtrl).
My SetItemState() to set the ith element to selected looks like this:
MyList_.SetItemState( i, LVIS_SELECTED | LVIS_FOCUSED, LVIS_SELECTED | LVIS_FOCUSED );
I tried calling it right after calling SetItemCount(), but it doesn't work, even if I give the list control focus.
Speaking of focus, maybe this could be part of the problem. The way my dialog is designed, I have an edit control sitting on top of the list control where the user can start typing in the edit control, and I then highlight/select the nearest match in the list control. So unless they actually click on an item in the list, the focus is in the edit control where they are typing, and I'm trying to select item in the list control. It does work using the simulated mouse click, but another very minor thing is that it looks like with CListCtrl, the highlight is blue if the control has focus, and gray if it doesn't have focus. It would be nice if I could keep the highlight blue all the time, the way CListBox works. So I know even if I can get it to highlight the first item by default, it will only have the gray highlight, not the blue that I would prefer. (That's probabaly not easy to change, huh?)
I originally was just using a CListBox and everything worked great, was simple, had no problem at all. Except the list is so large (~100,000 items) that it was a little slow to load, so I decided to try my hand at a virtual list, which also meant having to change to a CListCtrl, and seems to have introduced a number of minor issues that I've been struggling with.
Does this give you any more idea how I should be handling this? Thank you very much for your help.
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This should be the proper sequence after SetItemCount():
GotoDlgCtrl(&MyList_);
MyList_.SetItemState(0, LVIS_SELECTED | LVIS_FOCUSED, LVIS_SELECTED | LVIS_FOCUSED );
GotoDlgCtrl(&MyEdit_); // optional - if you want initial focus on the edit control
Then return FALSE from OnInitDialog() (important!).
(make sure you comment out any fake mouse click stuff  )
That works for me - I just tested it.
Without setting the focus to the list before setting the selection, it
indeed fails to select the item as you've seen - I confirmed that as well.
AmVal wrote: I don't know if this ancient version I'm using has SetItemCountEx()
That's why I gave you the Win32 equivalent
You can get the Win32 equivalent of anything missing from your ancient MFC
version here: List View Control[^]
AmVal wrote: It would be nice if I could keep the highlight blue all the time
You'd have to use custom draw for that.
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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Hmmm... Everything you say makes sense, but for some reason this is not working for me with the virtual list control (it does work for non-virtual).
This is pretty much what I had been trying, and I had also previously tried calling SetItemState() with one, or the other, or both LVIS_SELECTED and LVIS_FOCUSED, and even with only LVIS_SELECTED it didn't / doesn't work for me.
I'll keep looking to see if I can find something else wrong somewhere...
But I thought functionality was supposed to work the same for CListCtrl whether virtual or not, which makes it seem like it could be a bug in the version I'm using...
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Hmm I'm stumped 
I personally would use a message posted at the end of the OnInitDialog
to the dialog itself, then in response to that message do the item select.
I really don't like simulated clicks and /or keystrokes
If I think of something I'll let you know....good luck
Mark
Mark Salsbery
Microsoft MVP - Visual C++
![Java | [Coffee]](https://www.codeproject.com/script/Forums/Images/coffee.gif)
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I would prefer not to use the simulated mouse click, that was a last resort. But it appears I may have to, as without it, right now I can't select anything in the list when the user types in the edit control. The mouse click takes care of everything except the initial display. There's gotta be a way to do the same thing on initial display, I just can't figure out where to do it.
If it's not too much trouble, could you give me an example of the code you are suggesting so I can try it?
I'm pretty new to Windows/MFC programming (this is the first time I've even used CListCtrl, much less sent messages, etc. Each step of the way has been a real struggle, looking for examples I can follow, etc. (although I'm learning a TON which is cool!) Even though I don't really like the idea of the simulated mouse click, I was actually kind of impressed that I got it to work
So anyway, a sample of the code you are suggesting would just save me some time trying to figure out how to do it! Thanks a bunch.
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AmVal wrote: right now I can't select anything in the list when the user types in the edit control.
Wow - I thought it was just the original selection...
There's something wrong somewhere....you should be able to change
item states anywhere.
What version of Visual Studio are you using?
Mark Salsbery
Microsoft MVP - Visual C++
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It's Visual Studio 97. (Yikes! I know...)
The one article I referenced from 2000 was by a guy who sounded like a pretty experienced programmer, and he also discovered that programmatically selecting items in a virtual list control didn't seem to work. He never found any solution other than the fake mouse click. It sounded like he did get it to work for the initial selection as well. Unfortunately his code isn't out there any more so I can't see where he did that! (I don't know what version he was using, but his article was from 2000)
If I make the list box non-virtual, I can programmatically select items fine at any time. But as soon as I make it virtual, I can't programmatically select at all.
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AmVal wrote: It's Visual Studio 97. (Yikes! I know...)
I'm worried MFC had its own version of the control then.
I just can't remember 
These days (since Windows 98), the control is provided by
the operating system. You may want to not use MFC for the
control and use Win32 APIs directly. The problem seems to be
in MFC, not in the control.
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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You're right, if I just use:
ListView_SetItemState(MyList_, i, LVIS_SELECTED, LVIS_SELECTED)
It works to select the first item on initial display, as well to select at any other time. So I can avoid the fake mouse clicks! Yeah!
Thanks so much Mark!
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Cool! Thanks for the update
Cheers,
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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You can also do this:
//GotoDlgCtrl(&MyList_);
MyList_.SetItemState(0, LVIS_SELECTED, LVIS_SELECTED);
GotoDlgCtrl(&MyEdit_); // optional - if you want initial focus on the edit control
It seems you can't set LVIS_FOCUSED unless the control has focus.
And if the control doesn't have focus and you try to specify LVIS_SELECTED | LVIS_FOCUSED,
it doesn't set either state
Good to know!
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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I'm not expert on exceptions. I need to catch some memory exception and ignore it, but it des not work. It only works in debug release (exception is ignored), but in release mode it crashes like when I don't handle the exception. What is the problem?
Here is code :
try
{
*((char*)0)=1;
}
catch(...)
{
}
It is MFC app in VC6.0.
Thank you.
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This is the difference between C++ typed exceptions and Win32 structured exceptions. What you have is the former. See _set_se_translator() for more.
"Love people and use things, not love things and use people." - Unknown
"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch
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Thank you. I'm going to check it.
I wonder why debug mode caught the exception. Does debug mode use some default translator?
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rrrado wrote: I wonder why debug mode caught the exception.
I'm really not sure, but it may have to do with the optimizer.
"Love people and use things, not love things and use people." - Unknown
"The brick walls are there for a reason...to stop the people who don't want it badly enough." - Randy Pausch
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rrrado wrote: I wonder why debug mode caught the exception
Might be because you set the "Enable C++ Exception=> YES with Structured exception (/EHa)" for debug configuration settings but not for release configuration.
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In C++ - assuming the implementation follows the standard - catch is only allowed to catch exceptions raised using the throw keyword: since this isn't the case in your example the code in the catch block should NOT be executed. MSVC6 got this wrong but the bug has been corrected in later versions. The /EH[^] switch can be used to reinstate the bug.
Steve
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Hi all...
I'm using CxImage to load and draw PNG. Either in dialog box or preferably on desktop screen.. Need help how to draw the PNG. So far i did this.
CxImage* newImage = new CxImage();
newImage->LoadResource(FindResource(NULL,MAKEINTRESOURCE(IDR_PNG1),"PNG"),CXIMAGE_FORMAT_PNG);
Thanks.
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For PNG files you can use of CImage class and its easy to use.
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I guess Cimage and CxImage are sort of same thing..
Neverthless how can i do with Cimage Class..
Thanks..
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Surely CxImage must have rendering methods.
Look for methods called Draw()
Mark
Mark Salsbery
Microsoft MVP - Visual C++
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