C / C++ / MFC

Threads and CommandButton

20-Apr-05 9:31

One way is to use the IAccessible interface, specifically the get_accValue() method.

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

bigity20-Apr-05 7:38

bigity

20-Apr-05 7:38

Hi, I'm trying to write a basic Battleship game that can be played over the internet VIA a socket client/server set up.
I'm using MFC.

When the user clicks a button, it sends a message to the server where they clicked, the server then relays that on to the client. When the client receives it, they send a message back if it was a hit, or miss.

I have a thread that runs to get messages from the server, so I can have a chat running at the same time. So when the thread for receiving server messages gets a message back telling them if their shot was a hit or miss, I want to update the status of the buttons that I use for showing moves, by changing the forecolor of the button.

the code i use is --

<br />
the type of button is:  CCommandButton : CWnd (Which is used as a wrapper for the ActiveX command button)<br />
CCommandButton l_Buttons[10][10];<br />

then inside of my server message thread i use the code:

<br />
l_Buttons[0][0].put_BackColor(0x0000FF); //red<br />

I can put that same code into a non-threaded function and it works exactly how I want it to. Confused | :confused:

Is there any way I can fix this?

Thank you!

Re: Threads and CommandButton

David Crow20-Apr-05 9:33

Re: Threads and CommandButton

20-Apr-05 9:33

This sounds like a race condition, a common problem when multiple threads are involved.

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

bigity20-Apr-05 10:40

bigity

20-Apr-05 10:40

I think I am going to end up using two ports on my program. One for server messages and one for chat. Hopefully that'll fix it.

command.com (DOS)

includeh1020-Apr-05 7:29

includeh10

20-Apr-05 7:29

i am wondering if the program is an executable file -
because file extension of the program is com (not exe).

where is help of the program (for its command)? i can not find in my computer.

includeh10

Re: command.com (DOS)

David Crow20-Apr-05 9:44

removing untitled from title bar mfc

20-Apr-05 9:44

Yes, files having a .com extension are indeed executable. It used to be that in order to create such a file, the tiny memory model had to be used (because of the need for a single 64KB data and code segment). I'm not sure how they are created nowadays since memory models are a thing of the past.

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

lino_i20-Apr-05 6:12

lino_i

20-Apr-05 6:12

hello,

cs.style &= ~FWS_ADDTOTITLE

i know the following code does removes untitled from title bar however can anyone explain what is happening. i am not familiar with ~ used in this way? and are we passing the address to cs.style?

thanks,

Lino

Re: removing untitled from title bar mfc

RChin20-Apr-05 7:21

RChin

20-Apr-05 7:21

This code basically performs a logical operation on the cs.style variable; specifically removing the value indicated by FWS_ADDTOTITLE.
The ~, by the way, is the C++ NOT operator.

Have a read through this[^] article that explains in more detail.

I Dream of Absolute Zero

Re: removing untitled from title bar mfc

David Crow20-Apr-05 9:46

20-Apr-05 9:46

The value of FSW_ADDTOTITLE is 0x00008000. The ones complement (which is what the ~ symbol represents) of that is 0xffff7fff. When those bits are ANDed to whatever value cs.style currently has, the net result is that 0x00008000 is removed.

"Ideas are a dime a dozen. People who put them into action are priceless." - Unknown

BSTR*

Manikandan20-Apr-05 5:42

Manikandan

20-Apr-05 5:42

I got to use an activeX control in my VC++ project. When I import the control its wrapper class had a function as below,

void CVTSID::Connect(BSTR* RemHost, long* RemPort)
{
static BYTE parms[] = VTS_PBSTR VTS_PI4;
InvokeHelper(0x60030012, DISPATCH_METHOD, VT_EMPTY, NULL, parms, RemHost, RemPort);
}

I tried to pass the parameters as below,

CString str = "192.168.1.155";
BSTR host = str.AllocSysString();
long port = 3246;
m_dvt.Connect(&host,&port);

The function fails!

How I should pass the parameter Confused | :confused:

Re: BSTR*

James R. Twine20-Apr-05 7:44

CryptVerifySignature problem

20-Apr-05 7:44

CString str = "192.168.1.155";<br />
BSTR host = str.AllocSysString();<br />
long port = 3246;<br />
m_dvt.Connect(&host,&port);

First, you are going a really long way just to create a BSTR, you can save yourself one allocation:

CComBSTR bstrHost( "192.168.1.155" );<br />
long port = 3246;<br />
m_dvt.Connect(&bstrHost,&port);

   Second, what error is being returned? It looks like you are calling the method correctly, was the object created correctly?

   Third, when you have to pass pointers to a COM method, it is often because you are going to get something back from the method via those pointers. COM rules state that if you pass a BSTR pointer, you own whatever BSTR comes back via that pointer, and you transfer ownership of the BSTR you sent, if any. CComBSTR will automatically deallocate the BSTR (either the one it created, or the one you get back) when its destructor fires.

   Peace!

-=- James

If you think it costs a lot to do it right, just wait until you find out how much it costs to do it wrong!
Tip for new SUV drivers: Professional Driver on Closed Course does not mean your Dumb Ass on a Public Road!
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Re: BSTR*

Manikandan20-Apr-05 19:56

Manikandan

20-Apr-05 19:56

I receive two errors,

1."Run-time error'9': Subscript out of range" from activeX control itself.

2."Application-defined or object-defined error" thrown by the application.

Re: BSTR*

Manikandan20-Apr-05 22:55

Manikandan

20-Apr-05 22:55

I came to know the problem is within the activeX control itself. I download the latest control and its working fine without errors.

Thank you James.

SS0587020-Apr-05 5:31

SS05870

20-Apr-05 5:31

Hi,
I'm trying to code a program to verify the digital signature of several exe, dll,... files. The problem is that I don't have the certificate nor signature that is applied to those files, and neither I know if I need them D'Oh! | :doh:

. I've been looking to microsoft msdn CryptoAPI, but I could not get nothing clear out of the examples.

I suppose that I need to:
- extract somehow the signature or certificate from the loaded (BYTE*) file
- obtain a key form that certificate
- generate a hash value with CryptCreateHash and maybe later call CryptHashData?
- and finally call CryptVerifySignature praying for succes...

Any clues or full sources are welcome. I'm quite lost now Confused | :confused:

.
Thanks in advance.

Dragging URL's into a browser using COleDataSource

Taka Muraoka20-Apr-05 5:19

Re: Dragging URL's into a browser using COleDataSource

20-Apr-05 5:19

I'm trying to allow URL's to be dragged out of my app and into a browser. The relevant bit of code looks like this:

<br />
static COleDataSource gOleDataSource ;<br />
<br />
void CUrlDragDropTestDlg::OnLButtonDown(UINT nFlags, CPoint point) <br />
{<br />
    HGLOBAL hGlobal = ::GlobalAlloc( GMEM_MOVEABLE , 4096+1 ) ;<br />
    LPSTR pUrl = (LPSTR)::GlobalLock( hGlobal ) ;<br />
    strcpy( pUrl , "http://www.test.com" ) ;<br />
    ::GlobalUnlock( hGlobal ) ;<br />
    gOleDataSource.CacheGlobalData( RegisterClipboardFormat(CFSTR_SHELLURL) , hGlobal ) ;<br />
    DROPEFFECT dropEffect = gOleDataSource.DoDragDrop( DROPEFFECT_LINK|DROPEFFECT_SCROLL ) ;<br />
<br />
    CDialog::OnLButtonDown(nFlags, point);<br />
}<br />

This works fine for IE but not Mozilla/Firefox. Looking at what clipboard formats these apps use when dragging URL's *out* of them, the only one that seems to make sense is "UniformResourceLocator" i.e. the same one I'm using above. Dragging stuff *into* my app works fine, checking for this format.

However, when I try to drag my URL into Microsoft's IDataObject Viewer tool, it doesn't want to accept it so I'm guessing that I'm missing something. Anyone know what?

BTW, Opera doesn't seem to allow URL's to dragged at all WTF | :WTF:

Anyone know why they decided to do that?!

Lets be honest, isn't it amazing how many truly stupid people you meet during the course of the day. Carry around a pad and pencil, you'll have twenty or thirty names by the end of the day - George Carlin

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James R. Twine20-Apr-05 7:50

Re: Dragging URL's into a browser using COleDataSource

20-Apr-05 7:50

   My guess is that Mozilla/FireFox does not accept the CFSTR_SHELLURL format as a target. You could try using the CFSTR_INETURL format as well. See if you can drag a link from IE to Moz/FF. If you can, see what other CF formats it exposes in the D&D object.

   Do not forget that you should also make available other formats, like CF_TEXT/CF_UNICODE, so that you can interoperate easily with other applications.

   Peace!

-=- James

Taka Muraoka20-Apr-05 21:17

Re: Dragging URL's into a browser using COleDataSource

20-Apr-05 21:17

James R. Twine wrote:
My guess is that Mozilla/FireFox does not accept the CFSTR_SHELLURL format as a target.

This is really weird. You'd think Firefox would accept what it's putting out Roll eyes | :rolleyes:

These are the clipboard formats that each browser puts out when dragging a link:

Dragging a link from IE (into my app):
	UntrustedDragDrop
	FileGroupDescriptor
	FileGroupDescriptorW
	FileContents
	UniformResourceLocator

Dragging a link from Firefox (into my app):
	13
	FileGroupDescriptor
	FileContents
	UniformResourceLocator
	13
	13
	text/_moz_htmlcontext
	text/_moz_htmlinfo
	text/html
	HTML Format
	13
	1
where 13=CF_UNICODETEXT and 1=CF_TEXT.

text/_moz_htmlcontext is the HTML page, text/_moz_htmlinfo some binary data.

I then tried dragging links into IDataObject Viewer:

Dragging a link from IE into IDataObjectViewer:
- not allowed 

Dragging a link from IE into IDataObjectViewer:
	Unknown Clipformat
	FileGroupDescriptor
	FileContents
	UniformResourceLocator
	Unknown Clipformat
	Unknown Clipformat
	text/_moz_htmlcontext
	text/_moz_htmlinfo
	text/html
	HTML Format 
	Unknown Clipformat 
	CF_TEXT

Dragging a link between the two browsers:

Dragging a link from Firefox into IE: OK
Dragging a link from IE into Firefox: not allowed

I've also tried including various combinations of different clipboard formats.

James R. Twine wrote:
You could try using the CFSTR_INETURL format as well.

I can't seem to find a definition for this constant. The only references I found on the net defined it as "UniformResourceLocator" i.e. the same as CFSTR_SHELLURL Confused | :confused:

BTW, I got a lot of the way to where I am now by reading your hyperlink article. Thanks for that! Smile | :)

James R. Twine21-Apr-05 2:30

Re: Dragging URL's into a browser using COleDataSource

21-Apr-05 2:30

Well, I believe in the "when in Rome..." concept when dealing with cross-platform development. In Windows, a URL link, when dragged-and-dropped, has the format of CFSTR_SHELLURL, so that is what you use. When you wanna play in our sandbox, you follow our rules! Smile | :)

   As such, I would be of the opinion that those issues are (serious) bugs in those apps.

   If dragging from Firefox into IE actually WORKS correctly, you can figure out which format IE is accepting, and expose it yourself. I have to have enough faith in other developers that Firefox allows you do drag a link from one instance of itself to another, so there is at least one format it accepts...!

   Peace!

-=- James

Taka Muraoka21-Apr-05 2:37

Re: Dragging URL's into a browser using COleDataSource

21-Apr-05 2:37

I'm baffled at the results I got since I, too, generally trust programmers to get basic things like this right (and yes, Firefox allows drags to another instance of itself). The only format the two browsers seem to share is UniformResourceLocator but it doesn't seem to be working.

This is the point at which I give up, I think. Annoying, since I use Firefox most of the time. Sigh... Frown | :-(

Thanks for your help.

James R. Twine21-Apr-05 3:22

Re: Dragging URL's into a browser using COleDataSource

21-Apr-05 3:22

Are you sure you are exposing that format correctly? Also, it might look for another format as a "signature" that it is something it wants to accept.

Peace!

-=- James

Taka Muraoka21-Apr-05 8:38

Re: Dragging URL's into a browser using COleDataSource

21-Apr-05 8:38

James R. Twine wrote:
Are you sure you are exposing that format correctly?

What do you mean by "correctly"? The fact that the URL I am exposing is not being accepted by IDataObject Viewer makes me suspicious that I'm doing something wrong but having said that, it doesn't want to take URL's dragged from IE either Roll eyes | :rolleyes:

The code I'm using was included in my original post.

James R. Twine25-Apr-05 14:55

Re: Dragging URL's into a browser using COleDataSource

25-Apr-05 14:55

   I think I see the problem. Change DROPEFFECT_LINK to DROPEFFECT_COPY.

   The DROPEFFECT_LINK style has nothing to do with hyperlinks, it has to do with COM/OLE Linking. Also, remove the DROPEFFECT_SCROLL style, I believe that it is not supposed to be specified directly by the drag-source, just received by the drag-target.

   Peace!

-=- James

Taka Muraoka26-Apr-05 1:24