C / C++ / MFC

19-Mar-07 11:43

hey im having a rich edit problem.. lets say the control has some text.. more than its height size.. and you resize the rich edit in the dialog's WM_SIZE event from the bottom of the dialog to down youll see that the text in the rich edit remains at the same location and down there will be some empty space but the scrollbar position is down and when you click the scrollbar the text will go down at the bottom of the rich edit control where it should be when i resize it as well
i tried so many methods of forcing the control to scroll down there but no one was really efficient and right
for example i have this method

[code]
void CDDlg::OnSize(UINT nType, int cx, int cy)
{
CDialog::OnSize(nType, cx, cy);
m_richedit.MoveWindow(200, 200, cx - 200, cy - 200, FALSE);
m_richedit.PostMessage(WM_VSCROLL, SB_BOTTOM, 0);
m_richedit.Invalidate();
}
[/code]

when i resize the dialog everything seems to work right but i can see the rich edit flicker the text up and then down which is pretty annoying..
i tried finding the message which tells the richedit that i resized it and make it not send the message.. but i couldnt really find it

then i thought using LineScroll but i never figured it out how it works.. it doesnt really work right for me

please think about both methods and tell me how i could do it right..
LineScroll seems ok.. but i kind of dislike the idea of a line scroll.. i use the rich edit as a chat window and it seems better if it has smooth scrolling instead of line scrolling

anyway i cant really understand microsoft.. they released many versions of this control and never noticed their bug ??? i mean look at word pad which uses a rich edit control and do what i said above and resize it down after you add a lot of text.. youll see what happens which is very stupid IMO

please help me.. im trying to fix this bug for many months ( im not joking ) and i cant continue my project.. im sure this will help many other people..

thanks

x87Bliss19-Mar-07 12:42

Re: CRichEditCtrl problem [modified]

19-Mar-07 12:42

I never experienced this problem myself, but I did just dabble with it in Wordpad as you said, and I see what you're talking about. As you resize down it adjusts the scroll-bars range in respect to the size of the data, but it ignores the current scroll location being below the end of the data.

I don't know what you have already tried. I would try to get a handle to the scroll-bar and use "SetScrollPos" and see if that forces an update. To prevent it from changing, you may try "SetScrollPos(GetScrollPos())" or similar, I don't know the return types or parameters of these functions off the top of my head, but that would in essence tell it the user has scrolled, although the position won't really change, but it may force it to redraw the text in the right spot.

Another thing you can try is RedrawWindow() maybe.

Again, these are just little workarounds that may work, but I'm sure it's not the "right" way to do it. But maybe it'll get the job done. I've never tried them myself either, just what I would try if I was doing it.

Good Luck

xtexistenz19-Mar-07 12:55

19-Mar-07 12:55

hey, thanks for the reply
i have tried those before.. and no luck

m_richedit.SetScrollPos(SB_VERT, m_richedit.GetScrollPos(SB_VERT));
m_richedit.RedrawWindow();

they don't do anything

if you have any more ideas please post them here

thanks Smile | :)

btw you never experienced it because you never used the control ? or you never noticed it ? (just curious)

-- modified at 19:01 Monday 19th March, 2007

x87Bliss19-Mar-07 13:04

19-Mar-07 13:04

I've used the control, but not extensively enough to notice the problem. I've used it to write a paragraph worth of info basically, never had to use the scrolls. I was just saying that I don't have experience with the problem, but I was trying to offer things I would try as a solution if I did have that problem, but I see you're ahead of me, lol.

I notice in Wordpad, when the problem occurs if I hit the down arrow on the scroll bar, it'll fix it. Have you tried using SendMessage to send messages to emulate the user doing that? I don't know what those messages are tho.

The other thing you can do which may be "wrong" is

int oldScrollPos = GetScrollPos(SV_VERT);
SetScrollPos(SB_VERT, 0);
SetScrollPos(SB_VERT, oldScrollPos);

so it scrolls to the beginning then back to the end. I don't like it myself, it's sloppy, but if you want you can try it.

xtexistenz19-Mar-07 13:10

19-Mar-07 13:10

ah ok :P

yes i tried PostMessage(WM_VSCROLL, SB_BOTTOM, 0); and SendMessage(WM_VSCROLL, SB_BOTTOM, 0);
they do not work right if i dont add an Invalidate() after that but even after i do.. they cause the annoying flicker problem which i said at my first post

your last solution doesnt work.. funny i can see the scrollbar flickering up and down but no change to the text area. lol.

thanks again Smile | :)

x87Bliss21-Mar-07 11:41

21-Mar-07 11:41

I recreated the problem in Wordpad, as you mentioned before, and created a program to send window messages to it to fix it. And this is what worked for me. You can send these messages from within your own program where necessary. I only made a seperate app, because I couldn't just rewrite wordpad :-P

::SendMessage(HandleOfRichEditControl, WM_VSCROLL, SB_LINEDOWN, 0);
::SendMessage(HandleOfRichEditControl, WM_VSCROLL, SB_ENDSCROLL, 0);

The one with ENDSCROLL may not be needed, but it is sent after LINEDOWN when I press the down arrow on the scroll bar. So it may be needed for more accurate emulation of the user pressing it. Who knows.

xtexistenz25-Mar-07 13:51

25-Mar-07 13:51

ah sorry for the late reply.. yeah it works.. same goes for SB_BOTTOM but the problem is it creates some flicker.. you could see the lines going up and then down very fast.. i just need to find a way to scroll it down and not have that flicker.. thats all and i have no idea..

thanks

x87Bliss25-Mar-07 21:34

25-Mar-07 21:34

It should only flicker as you're resizing, which shouldn't be that big of a deal? If it's flickering all time you probably have the scrolling code in the wrong place.

A lot of controls flicker during resize AFAIK. You should be able to search up ways around that. I think it involves drawing the dialog off-screen and then repainting it on-screen, like a double buffer. I'm sure there are other ways too. I just know that you'll be able to find something.

xtexistenz26-Mar-07 7:21

26-Mar-07 7:21

that flicker is because the rich edit always scrolls the caret into view.. which is a scroll by line.. to get rid of that flickering i would have to disable that rich edit "feature" i dont think you understood what i meant by flickering.. its not the standard light flickering.. its a very bad flicker which can be very annoying on slower pc's, it moves the whole text up one line then down.. this is very noticeable.. i tried many ways.. like ignoring WM_PAINT while resizing but didnt make any change.. i got no idea

x87Bliss26-Mar-07 15:36

26-Mar-07 15:36

Have you tried SetSel to move the caret to the end of the text, so this way it doesn't have to scroll it into position.

SetSel, I think that's the name, should take 2 parameters, the first selected character and the last selected character. If they are the same, then it just moves the caret to that position.

Should be something like...

int Length = GetLength();
SetSel(Length, Length);

SetSel may even have a third bool parameter too that tells it whether to scroll to the newly selected text.

Using SetSel and telling it to scroll to the newly selected text may even fix the other scrolling problem. Good Luck.

xtexistenz26-Mar-07 20:47

26-Mar-07 20:47

thanks, SetSel only has 2 parameters.. anyway i meant even if the selection was at the end of the text it still tries to scroll it in its way (like line by line) which causes the flicker, when i try to force it stay down it first goes up one line and then down

i hope this made sense.. if not please tell me and ill explain again :P

if there was a way to slow down the PC a lot or just the application you could see it very clearly whats happening lol

btw i dont think i have said this before.. but if you look at MSN Messenger you will see that it doesnt have any flickering problem and im pretty sure it uses the rich edit control.. but yea its made by microsoft so they know the rich edit's secret lol
but theres also GameSpy Arcade.. which works without a problem i dunno how they do it.. all i see is that they put in a custom scrollbar.. but i dont see how that helped this is because of auto vscroll, actually really check this out.. remove the auto vscroll property and it will never flicker.. you have to remove vertical scroll as well..

network query

lucy19-Mar-07 10:05

19-Mar-07 10:05

I have a windows client application, which I want to use to communicate with a server application running on a different machine in the same LAN. To make it user friendly, instead of asking the user to input the host IP addres of the server to the client application, I want the client application to do a query in the LAN, and find out what the candidate server's IP address is, and all the user has to do is to confirm that that's the one to communicate with.

I have no clue how I can get this done. Any hint would be greatly appreciated. Thanks a lot!

Ravi Bhavnani19-Mar-07 10:19

Ravi Bhavnani

19-Mar-07 10:19

This[^] control will provide the source code to determine the list of visible servers on the LAN.

/ravi

This is your brain on Celcius
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lucy19-Mar-07 10:47

19-Mar-07 10:47

ravi, Thank you for the link.

but the server I am thinking of is not a generic server. It's just an application which runs on another computer, but serves as server in a client/server software.

maybe I can use broadcast function, but is there any better way to implement it?

for example, D-Link has a network storage adapter DNS-120. It has a built-in FTP server, so files can be accessed over the internet, when the disk is connected to this adapter. It has an application called "Easy Search", which is to easily locate DNS-120 units for configuration.

What I want is similar to this "Easy Search", that is, click a button on this "Easy Search" application, it will return the IP addresses of my "DNS-120" units in the same LAN.

English is not first language, so I hope I made myself a bit more clear now.

Thank you for any hint!

Ravi Bhavnani19-Mar-07 11:01

Ravi Bhavnani

19-Mar-07 11:01

lucy wrote:
application called "Easy Search",

Discovery mechanisms such as this (and license severs) work by listening on a specific port. The server code needs to support a ping/ack request, in which case, all you need to do is ping the specific port on all visible servers in your LAN. The ones that respond are eligible candidates for your client.

The ping/ack support can be made more useful if the server is smart enough to return additional information (eg: load, etc.) which would make it easier for your clients to select the appropriate one.

Hope this helps!

/ravi

PS: Your English is fine. Smile | :)

This is your brain on Celcius
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lucy19-Mar-07 11:27

19-Mar-07 11:27

thank you very much, ravi.

now I understand the principle. Is there any tutorial material I can read to learn more? I'm pretty new to the network programming. what I have done is limited to very basic stuff, such as one-to-one send/recv applciation.

thanks again!

David Crow19-Mar-07 15:09

David Crow

19-Mar-07 15:09

lucy wrote:
I want the client application to do a query in the LAN, and find out what the candidate server's IP address is...

Use NetServerEnum() for this.

Once you can successfully enumerate through all machines in your LAN, then you can go about "pinging" their ports.

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

lucy20-Mar-07 7:49

20-Mar-07 7:49

thank you, this is very helpful.

I then found this article:
http://www.codeproject.com/internet/ipaddress.asp[^]

now I'm on my way to the solution.

Thanks again!