C / C++ / MFC

26-Jun-01 16:43

FYI. You can delete your posts using the [Delete] link found at the bottom right corner of every posting.

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Multitasking: Screwing up several things at once.

ScaleX for C++?

Craig Miller26-Jun-01 14:18

Craig Miller

26-Jun-01 14:18

Hi,

I'm converting some old vb code to a VC++ application and there is this function called ScaleX which converts a coordinate from twips to pixels. Is there any equivalent function in VC++?

Thanks for any help you can provide,

Craig

Re: ScaleX for C++?

Tomasz Sowinski27-Jun-01 2:28

Can I programmatically access the running process list?

27-Jun-01 2:28

You can do this using two different methods:

1) set the mapping mode of device context to MM_TWIPS, then call DPtoLP.

2) perform calculations 'manually' using value returned from GetDeviceCaps(hdc, LOGPIXELSX) - it's a number of pixels per 'logical inch'.

int logpixx = GetDeviceCaps(hdc, LOGPIXELSX);
int pix = logpixx * twips / 1440;

Tomasz Sowinski -- http://www.shooltz.com.pl

Jon Sagara26-Jun-01 13:22

Jon Sagara

26-Jun-01 13:22

Hello,

Is it possible to get a process's PID if the name of the application is known? Is there a function such as "GetProcessIdByName", or is there some alternative hack? BTW, I am developing with Visual Studio 6 for Windows NT/2000, and using the July 2000 Platform SDK.

Thanks for any help,

Jon Sagara

Re: Can I programmatically access the running process list?

Jon Sagara26-Jun-01 14:44

Jon Sagara

26-Jun-01 14:44

Another user's question actually answered mine. For those who are interested, please see the following MSDN article:

http://support.microsoft.com/support/kb/articles/Q175/0/30.ASP

Thanks,

Jon Sagara

"When I was fourteen, I was amazed at how unintelligent my father was. By the time I turned twenty-one, I was astounded how much he had learned in the past seven years." -- Mark Twain

File I/O

John Uhlenbrock26-Jun-01 12:34

John Uhlenbrock

26-Jun-01 12:34

I need to open a file from one function then manipulate it in another. How do I pass the stream to the second function.
I am using the fstream header file for I/O..

Re: File I/O

Ben Burnett26-Jun-01 14:19

Ben Burnett

26-Jun-01 14:19

Try passing the stream object by reference.

-Ben

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On the topic of code with no error handling -- It's not poor coding, it's "optimistic" Wink | ;)

Re: File I/O

John Uhlenbrock27-Jun-01 6:37

John Uhlenbrock

27-Jun-01 6:37

I thought that was all I had to do. I must be doing something wrong with syntax or something... Here's the jist of what I am doing....

#include <fstream.h>

void ReadFile(ifstream &stream);

int main()
{
ifstream in;

in.open(FileName);

ReadFile(in);
}

ReadFile(ifstream &stream)
{
}

I get compiler errors n'stuff. I'm not passing the stream object correctly I believe...

Re: File I/O

Ben Burnett27-Jun-01 9:49

Ben Burnett

27-Jun-01 9:49

I think you problem is that;

a) you need to include both <iostream> and <fstream>
b) you need to bring the classes declared in the std namespace into scope.

I re-wrote it to do all of this;

#include <iostream>
#include <fstream>
using namespace std;

void ReadFile ( ifstream & stream );

int main () {

	ifstream fin;
	
	// open the file
	fin.open ( theFileName );

	// read from that file
	ReadFile ( fin );

}

void ReadFile ( ifstream & stream ) {

	// do some reading...

}

That should do it for you.

-Ben

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On the topic of code with no error handling -- It's not poor coding, it's "optimistic" Wink | ;)

SetRange for CSpinButtonCtrl

Jerry Wang26-Jun-01 11:59

26-Jun-01 11:59

Hi, I am a new to C++ MFC design so thanks in advance for the inputs.

I am wondering if anyone can tell me where is the best place to put the SetRange(int, int) command for a spinner inside a modeless propertyPage. I understand the usual place is in OnInitDlg. However, I don't think there is a similar OnInit function for my property page/sheet.

Thanks!
Wink | ;)

Tomasz Sowinski27-Jun-01 2:38

27-Jun-01 2:38

OnInitDialog is OK, assuming that range remains the same during the lifetime of your object.

Tomasz Sowinski -- http://www.shooltz.com.pl

Jerry Wang27-Jun-01 9:53

27-Jun-01 9:53

Yes, I would put SetRange in OnInitDialog too in a heart beat, but CPropertySheet class does not have the OnInitDialog function for me to inherit like in CDialog... so I'm lost for ways there.

Tomasz Sowinski27-Jun-01 10:05

27-Jun-01 10:05

Just use this:

BOOL CYourPage::OnInitDialog() 
{
CPropertyPage::OnInitDialog();
// your stuff here
return TRUE;
}

Tomasz Sowinski -- http://www.shooltz.com.pl

Jerry Wang27-Jun-01 10:37

27-Jun-01 10:37

Hmm.. there is no OnInitDialog() fcn in CPropertyPage or any of its parents. This exactly what I am stuck on. I know I can initialize my SetRange in OnInitDialog if I had a dialog, but I don't I have a CPropertyPage.

btw, the tree for these classes is:

. . . . . . . . . . . . . . . . . . . . . . . .-> CDialog . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . / . . . . . . . . . . .
CObject -> CCmdTarget -> CWnd -<. . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . \ . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . .-> CPropertySheet. . .

So there's no OnInitDialog for CPropertySheet.

Tomasz Sowinski27-Jun-01 10:40

27-Jun-01 10:40

CPropertyPage derives from CDialog - your tree is not based on facts Smile | :)

. If you insert CPropertySheet::OnInitDialog() into CYourPage::OnInitDialog, the CDialog::OnInitDialog will be called.

Anyway, if you don't want to use OnInitDialog, use OnSetActive or DoDataExchange instead.

Tomasz Sowinski -- http://www.shooltz.com.pl

Jerry Wang27-Jun-01 10:56

27-Jun-01 10:56

Ah, yes you are correct! I was looking into the wrong place -- the CPropertySheet, instead of CPropertyPage. Thanks! My spinner works like a charm now Smile | :)

CEdit

26-Jun-01 11:07

I intend to add a CEdit box to the main window (a drawing program which is NOT Dialog based) so I can always show the x,y coordinates in that box. I've added such a variable to the View class and created it in the constructor, but it does not appear in the main window, how can I make it display?

PJ Arends26-Jun-01 17:06

26-Jun-01 17:06

You have to create the edit control in your view's OnCreate() handler.

int CTestView::OnCreate(LPCREATESTRUCT lpCreateStruct) 
{
	if (CView::OnCreate(lpCreateStruct) == -1)
		return -1;
	
	// TODO: Add your specialized creation code here
	m_myEdit.Create(WS_VISIBLE|WS_CHILD|WS_BORDER, CRect(10,20,30,40), this, ID_MYEDIT);
	return 0;
}

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Multitasking: Screwing up several things at once.

27-Jun-01 8:29

Thanks. I've successfully added it. I also added a combobox on the window, which dynamically contain some string. What I want is that when make a choice in the combobox, the code will do different things, how can I do that? It's simple in Dialog based program, but I have no idea how to do that in non-Dialog-based.

PJ Arends27-Jun-01 15:18

27-Jun-01 15:18

You do it exactly the same way as in a dialog. You just have to do it manually, classwizard will not help you. Add your message map entries and member functions.

BEGIN_MESSAGE_MAP(CTestView, CView)
	//{{AFX_MSG_MAP(CTestView)
	ON_WM_CREATE()
	//}}AFX_MSG_MAP
        ON_CONTROL(CBN_SELCHANGE, ID_MYCOMBO, OnSelChanged)
END_MESSAGE_MAP()

void CTestView::OnSelChanged()
{
        DoSomethingWhenSelectionChanges();
}

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Multitasking: Screwing up several things at once.

27-Jun-01 17:32

I tried but it does not work. I also tried to change ON_CONTROL to ON_NOTIFY, it does not work either. The function, say CTestView::OnSelChanged() should be declared with type "afx_msg", right? Is there any other trick besides what you said above? By the way, my application is a windows CE program, could this be the reason?

PJ Arends27-Jun-01 18:19