C / C++ / MFC

Michael Dunn5-Jul-02 8:14

Michael Dunn

5-Jul-02 8:14

See FAQ 2.2

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lucy5-Jul-02 9:35

lucy

5-Jul-02 9:35

thank you! I updated the SDK and there is no problem now.

Aaron Schaefer12-Aug-02 9:18

Aaron Schaefer

12-Aug-02 9:18

Hi Lucy,

Have you found a way around this problem? I am running into the same difficulty.

Thanks,

Aaron

lucy13-Aug-02 13:41

lucy

13-Aug-02 13:41

yes, check the above answers. I updated the library (from MS web site) and the problem went away.

Listview redraw problems

CaesarCZ5-Jul-02 7:13

5-Jul-02 7:13

Hi,
I'm filling my listview with new item about each 3-4 secs... But the customer wants it to stop blinking (which is due to the redraw each 15 sec). I saw some programs that didn't suffer from this but I wonder how they did it. Should I repaint the whole list on my own or? How should I deal with this?

Michael Dunn5-Jul-02 8:16

Michael Dunn

5-Jul-02 8:16

Call SetRedraw(false) then fill in the list contents. When you're done, call SetRedraw(true); followed by RedrawWindow()

--Mike--
Just released - RightClick-Encrypt v1.3 - Adds fast & easy file encryption to Explorer
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[James Pullicino]5-Jul-02 8:23

[James Pullicino]

5-Jul-02 8:23

There are several ways to deal with this problem.

1) When refreshing, don't delete all items and re-populate the entire list. Instead only delete the items which do not exist in the new list and update the ones which need updating. During this operation set Redraw() to FALSE.

2) Handle the LVG_GETDISPINFO message. You will find information about this in the MSDN. A Codeproject search may yield some results. If you don't find enough information about how to use this technique, tell me, and I'll write an article.

3) Set Redraw() to FALSE while deleting and adding items in the list. Display an hourglass.

Regards,

James Pullicino

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CaesarCZ5-Jul-02 8:40

5-Jul-02 8:40

1)I just ADD only ONE iteam about each 3-4 secs. I don't delete any items

2) LVN_GETDISPINFO: I don't understand how this could help me? Confused | :confused:

3)Even when I use this, it still blinks (as it redraws each 3-4 secs).

The only solution I could think of is to ownerdraw, filter out the erase background etc messages and just manully draw the item I added.

I could even have the items preloaded and just change the images as they load (yes, these are thumbnails, but the pictures are big and therefore take so long to load). But numerous apps with thumbnails don't blink when changing or adding their items. Like XnView or Ulead Photo Explorer. Thanks again

[James Pullicino]5-Jul-02 8:44

[James Pullicino]

5-Jul-02 8:44

I don't understand why it should flicker then. Can you describe whats happening in more detail? Like if it is a listview or listctrl, MFC what?

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CaesarCZ5-Jul-02 8:56

5-Jul-02 8:56

it's a WinApi application. I use a common controls listview control. The icons are 100x100 pixels. IMHO It flickers because I need to redraw it every while because I add an new item every while. I can send you the exe (92 kb) with the source if you want. But there's no "extra" stuff in it. Maybe the exe would show you the efect

[James Pullicino]5-Jul-02 11:06

[James Pullicino]

5-Jul-02 11:06

Why don't you just post the code which is called when the timer elapses?

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CaesarCZ5-Jul-02 12:58

5-Jul-02 12:58

when the timer elapses (when an image is loaded actually), this code takes place. It all is a part of the window proc. wParam is the number (array index) of the image to be added. hListBitmap is a initialized image list, hList is a window handle to the listview control, lpPictureList is my class for storing the images

//i tried this line to avoid the flickering, but it dosn't help
SendMessage(m_hList,WM_SETREDRAW,FALSE,0);

//i have and image list with the previous entries already set, so I just add the new one to it
ImageList_Add(hListBitmap, lpPictureList->GetPicture(wParam)->GetThumb(), NULL);
//I assign the image list to the listview
SendMessage(hList, LVM_SETIMAGELIST, (WPARAM)LVSIL_NORMAL, (LPARAM)hListBitmap);
//I add the new item
SendMessage(hList, LVM_SETITEMCOUNT, (WPARAM)1, (LPARAM)LVSICF_NOINVALIDATEALL | LVSICF_NOSCROLL);

LV_ITEM lvItem;

lvItem.mask = LVIF_TEXT | LVIF_IMAGE;
lvItem.pszText = lpPictureList->GetPicture(wParam)->GetFilename();
lvItem.iImage = wParam;
lvItem.iSubItem = 0;
lvItem.cchTextMax = 7;
lvItem.iItem = 0;

SendMessage(hList, LVM_INSERTITEM, 0, (LPARAM)&lvItem);
SendMessage(hList, LVM_SETITEMTEXT, 0, (LPARAM)&lvItem);

//the same as the first line
SendMessage(m_hList,WM_SETREDRAW,TRUE,0);

thanks in advance

CaesarCZ5-Jul-02 23:45

5-Jul-02 23:45

c'mon guys, please give me some hints at least... I really can't find any soulution.

Shog⁹6-Jul-02 17:11

Shog⁹

6-Jul-02 17:11

Not sure if i'm reading this right, but are you sending LVM_SETIMAGELIST and LVM_SETITEMCOUNT *each* time you add an item? This might have something to do with the flicker.

Otherwise, you *can* double buffer listviews, fairly easily as it turns out. Do a search on CP and in the C++ forum, this has come up before.

BTW: how bad of flicker are we talking about here? Optic-nerve-jerking, screen-tearing, unreadable flicker, or a minor blip?

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CaesarCZ7-Jul-02 0:18