Re: How to detect Internet connection on machine? - C / C++ / MFC Discussion Boards

Re: GDI+ Region and SetWindowRgn

Nishad S11-Sep-07 2:16

Nishad S

11-Sep-07 2:16

bob16972 wrote:
you've drawn the region using GDI and then with GDI+

Nop... the window region set is a little bit different than the path drawn by using GDI+. So there are some holes (area that's not drawn) in the edges of the window.

- NS -

trouble in using MAPIToMIMEStm help

monsieur_jj10-Sep-07 23:06

monsieur_jj

10-Sep-07 23:06

I have encountered Access violation reading location with this code:

IConverterSession* sample;
	sample = NULL;
	IStream *istream;
	istream = 0;
	sample->SetEncoding(IET_QP);
	sample->SetSaveFormat(SAVE_RFC822);
	hResult = sample->MAPIToMIMEStm(LPMESSAGE(msgName.c_str()), istream, CCSF_SMTP);
	if (hResult !=S_OK){ 			 		
		throw(HResultException("MAPIToMIMEStm ResolveMsg",0));
	 }

I am really new to this can anyone guide me in making this work?

Thanks a lot,
Jj

Re: trouble in using MAPIToMIMEStm help

Cedric Moonen10-Sep-07 23:18

Cedric Moonen

10-Sep-07 23:18

sample = NULL;<br />
....<br />
sample->SetEncoding(IET_QP);

Guess what will happen when you call a function on a NULL pointer ?
You first need to create an object (do you need to use pointers here, can't you simply create an instance of IConverterSession ?)

By the way, the debugger is your best friend Wink | ;)

Cédric Moonen
Software developer

Charting control [v1.2]

How to detect Internet connection on machine?

Sameerkumar Namdeo10-Sep-07 22:52

Sameerkumar Namdeo

10-Sep-07 22:52

I am using CWebBrowser2 wrapper in my dialog based application.
In the OnInitDialog() function I am calling Navigate() function of CWebBrowser2.
If the internet connection is not available on a machine then how can I generally detect that so that I can display some default thing in CWebBrowser2 control.
Can it be detected using CWebBrowser2 ?

Thanks.

Re: How to detect Internet connection on machine?

baerten10-Sep-07 23:26

baerten

10-Sep-07 23:26

At least you can realize a ping on a specific server.
Propably the CWebBrowser2 has this function...

Good luck

Re: How to detect Internet connection on machine?

David Crow11-Sep-07 3:12

David Crow

11-Sep-07 3:12

baerten wrote:
At least you can realize a ping on a specific server.

Pinging a machine is not reliable. Too many false-positives.

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: How to detect Internet connection on machine?

baerten11-Sep-07 3:38

baerten

11-Sep-07 3:38

That's right, but in case of no internet connection you have all the time a false result.

But it's anyway the latest possibility LOL

Re: How to detect Internet connection on machine?

bob1697211-Sep-07 17:06

bob16972

11-Sep-07 17:06

If you have a dial-up, the attempt to query an IP will cause the ISP authentication junk (dialog boxes) to kick in. We tried this back in 2002 and soon realized it caused too many issues on laptops that needed to connect at locations with modems but weren't connected at the time the software was being run.

You need to check the routing table, then maybe attempt a ping after you know there is some network connection.

There are a couple of different approaches to check for network connectivity before attempting to go out and touch another computer.

Re: How to detect Internet connection on machine?

jhwurmbach11-Sep-07 4:07

jhwurmbach

11-Sep-07 4:07

DavidCrow wrote:
Pinging a machine is not reliable. Too many false-positives.

You mean false-negatives? ICMP-requests to a live server filtererd out by a firewall?
You need to pick a server with ICMP running and not prone to stop that. I use "www.heise.de" for that. A german publisher of computer magazins with a very dedicated opinion on why ICMP-filterung is bad.

Though I speak with the tongues of men and of angels, and have not money, I am become as a sounding brass, or a tinkling cymbal.
George Orwell, "Keep the Aspidistra Flying", Opening words

Re: How to detect Internet connection on machine?

David Crow11-Sep-07 4:25

David Crow

11-Sep-07 4:25

jhwurmbach wrote:
You mean false-negatives?

Thanks.

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

Re: How to detect Internet connection on machine?

bob1697211-Sep-07 2:05

bob16972

11-Sep-07 2:05

The FAQ[^]

Re: How to detect Internet connection on machine?

bob1697211-Sep-07 2:08

bob16972

11-Sep-07 2:08

Or, a slightly more complicated way from Edwin Eefting &
Patrick Philippot posted on CodeGuru a while ago that appears to be fairly robust

Network connection[^]

Re: How to detect Internet connection on machine?

David Crow11-Sep-07 3:13

David Crow

11-Sep-07 3:13

ccpptrain wrote:
If the internet connection is not available on a machine then how can I generally detect that...

See if this helps.

"A good athlete is the result of a good and worthy opponent." - David Crow

"To have a respect for ourselves guides our morals; to have deference for others governs our manners." - Laurence Sterne

map file with 0 size

Vinod CS10-Sep-07 22:46

Vinod CS

10-Sep-07 22:46

Hi,
My code tries to map a file with createFileMapping(). The Problem is
when the file is not present, this function fails with GetLastErr saying
"The Volume for a file has been externally altered". I am attaching code sample:

HANDLE hCreateFile = CreateFile(  _T("E:\\size0.txt"), // file name with path <br />
                                       GENERIC_READ | GENERIC_WRITE, // Access mode<br />
                                       FILE_SHARE_READ, // Sharing mode<br />
                                       NULL,            // Security Attributes     <br />
                                       OPEN_ALWAYS ,  //   How to create<br />
                                       FILE_ATTRIBUTE_NORMAL, // File attributes<br />
                                       NULL                 // Handle to template file<br />
                                       );<br />
               <br />
        if( INVALID_HANDLE_VALUE == hCreateFile )<br />
        { err handling       }<br />
        // 2. Create a FILE mapping object<br />
        HANDLE hFileMap = CreateFileMapping( hCreateFile, // handle to the opened file <br />
                                             NULL,        // security attributes <br />
                                             PAGE_READWRITE, // protection<br />
                                             0,              // high-order DWORD of size<br />
                                             0,             // low-order DWORD of size<br />
                                             NULL           // mapping object name<br />
                                             );<br />
        <br />
        if( NULL == hFileMap ) // this return NULL when file size is 0.<br />
        { errHandling() }

How can I map a file with 0 Size? pls help

regds,
vinod

Re: map file with 0 size

Naveen10-Sep-07 23:13

Naveen

10-Sep-07 23:13

Vinod CS wrote:
How can I map a file with 0 Size? pls help

How much do u expect the shared memory size to be after mapping? 0 bytes?

nave

[OpenedFileFinder]

Re: map file with 0 size

Vinod CS11-Sep-07 17:42

Vinod CS

11-Sep-07 17:42

Acttually I want to append data to this file. But in the function where I am opening map of this file, I do not know how many bytes to append?

Vinod.C.S

Re: map file with 0 size

Sameerkumar Namdeo10-Sep-07 23:30

Sameerkumar Namdeo

10-Sep-07 23:30

From Jeffrey Richter's book ....

If you want to create the file-mapping object so that it reflects the current size of the file, you can pass 0 for both parameters. If you intend only to read from the file or to access the file without changing its size, pass 0 for both parameters. If you intend to append data to the file, you will want to choose a maximum file size that leaves you some breathing room. If the file on disk currently contains 0 bytes, you can't pass two zeros to CreateFileMapping's dwMaximumSizeHigh and dwMaximumSizeLow parameters. Doing so tells the system that you want a file-mapping object with 0 bytes of storage in it. This is an error and CreateFileMapping will return NULL.

Since you are using PAGE_READWRITE in CreateFileMapping....Your intension might be to write something in file whose size you have given to be 0 in CreateFileMapping.

I think you can map (using flag PAGE_READWRITE)file whose size is zero by specifying some number > 0 as dwMaximumSizeLow parameter of CreateFileMapping(). This number will be equal to no.of bytes that you want to write to file. The file will be expanded to that size if its size was initially zero.

bye.

Re: map file with 0 size [modified]

Vinod CS11-Sep-07 17:44

Vinod CS

11-Sep-07 17:44

thanks, I got the solution. I opened file with 1KB, if the file size is zero.

-- modified at 3:48 Wednesday 12th September, 2007

Vinod.C.S

PNG Alpha blending/channel in VC++ 6.0?

StarMeteor10-Sep-07 22:33

StarMeteor

10-Sep-07 22:33

Hi All,

I am writing an application which try to show PNG file as a dialog background using GDI+
I have successfully using the PNG as background (using Graphics::DrawImage()), however, I found that the loaded PNG seems not apply the alpha channel information. What I should do?

Thanks!

(sorry for repeat posting if there is any)

Vincent

Re: PNG Alpha blending/channel in VC++ 6.0?

Mark Salsbery11-Sep-07 8:04

Mark Salsbery

11-Sep-07 8:04

Where in your code are you calling DrawImage()?

What is the background behind the image and how is it drawn?

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: PNG Alpha blending/channel in VC++ 6.0?

StarMeteor11-Sep-07 16:45

StarMeteor

11-Sep-07 16:45

I called it at OnEraseBackground()

I would like to have a transparent background (i.e. I set the desktop background to black/white, I hope the image boundary will be "blur" with the work of alpha bending).

I am not sure if what I do is right, however, with using the Graphics::SetCompositingMode(), it seems that the Graphics::DrawImage() method will not directly apply the alpha bending information? ( I use Bitmap::GetPixelFormat() to verify the input image is a PixelFormat32bppARGB type, which means it should include the alpha channel)

Re: PNG Alpha blending/channel in VC++ 6.0?

Mark Salsbery12-Sep-07 6:17

Mark Salsbery

12-Sep-07 6:17

You shouldn't need much more than this...

    // Load a bitmap

    Bitmap SrcBitmap(L"C:\\Test.png", FALSE);

...

    // Draw the bitmap to the DC at 0,0

    Graphics DstGraphics(hdc);
    DstGraphics.SetCompositingMode(CompositingModeSourceOver);
    DstGraphics.DrawImage(&SrcBitmap, 0, 0, SrcBitmap.GetWidth(), SrcBitmap.GetHeight());

If something's not working I'd have to see a code sample to possibly help Smile | :)

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

Re: PNG Alpha blending/channel in VC++ 6.0?

StarMeteor12-Sep-07 17:21

StarMeteor

12-Sep-07 17:21

Hi Mark,

Thanks for your reply ^^

err... what I wrote right now is exactly same as yours... (even the file name )
however, the outcome is just a dark background but not transparent...

Maybe I put at a wrong message call location?
I put the above code under OnEraseBackground()

Vincent

Re: PNG Alpha blending/channel in VC++ 6.0?

Mark Salsbery13-Sep-07 5:24

Mark Salsbery

13-Sep-07 5:24

Hmm...do you have a sample of a png image that isn't working that you can send me to test?

Mark

Mark Salsbery
Microsoft MVP - Visual C++
Java | [Coffee]

dont replace the ok button coding in that ok button e want enter coding

yadahav10-Sep-07 22:02

yadahav

10-Sep-07 22:02

void CCURLASSIgnmentDlg::OnButton2()
{

CButton *b1;
CString s1,s2;
CEdit *e1=( CEdit *) GetDlgItem(IDC_EDIT1);
e1->GetWindowText(s1);

for(int i=IDC_RADIO1;i<=IDC_RADIO1+nob;i++)
{

b1=(CButton *) GetDlgItem(i);
b1->GetWindowText(s2);

if(s2.Compare(s1)==0)
{
return;
}
}
b1=(CButton *) GetDlgItem(IDC_RADIO1+nob);
b1->SetWindowText(s1);
e1->SetWindowText("");
nob++;
if(nob<18)
{

b1=(CButton *) GetDlgItem(IDC_RADIO1+nob);
b1->ShowWindow(SW_SHOW);
}
else
nob=17;

}
this is my assigement inthis assigement if i press the ok button than display the url.but i want if i dont change ok button but i want entercoding on that ok button.

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