C / C++ / MFC

27-Oct-02 21:38

Why can't I use static member variables inside member functions even using the scope resolution operator...???

I have the following and it won't work and i'm confused as to why not:

class myClass{
  // This doesn't work...WHY..???
  void MyFunc(){ myClass::m_myStatic = NULL; }

  UINT m_myStatic;
};

// Somewhere in the implementation file
UINT myClass::m_myStatic = NULL;

The above does work...but I get an unresolved external error when I try the extact same thing inside a member function...

Why can't I use static members inside non-static member functions...? I thought this is what the scope operator was for...???

Thanx! Smile | :)

"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

Daniel Strigl27-Oct-02 21:57

Daniel Strigl

27-Oct-02 21:57

1.) Add the static word to your static member!

static UINT m_myStatic;

2.) You don't need to write myClass::m_myStatic in your member function, just write m_myStatic.

void MyFunc(){ m_myStatic = NULL; }

class myClass
{  
    // This doesn't work...WHY..???  
    void MyFunc(){ m_myStatic = NULL; }  
    static UINT m_myStatic;
};

// Somewhere in the implementation file
UINT myClass::m_myStatic = NULL;

Daniel

---------------------------
Never change a running system!

alex.barylski28-Oct-02 6:33

28-Oct-02 6:33

Sorry that was a typo I had the static keyword there I just missed while typing...

Anyways, I still get the unresolved error:

// Interface
class myClass{
  public:
    static WNDPROC m_wndProc;
  protected:
    void SubclassMyWindow();
};

// Implementation
void myClass::SubclassMyWindow()
{
  m_wndProc = NULL; // Unresolved linker error
}

Even if I use the scope operator...whats going on...?

Cheers! Smile | :)

"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

ian mariano27-Oct-02 21:59

ian mariano

27-Oct-02 21:59

You don't have to clarify your variable with the scope operator because you're already inside your class scope:

class myClass
{
  static UINT  m_myStatic;
  void MyFunc(void)  {  m_myStatic = NULL;  }
};

You have to declare the member variable as static in your class definition before it's really static.

The implementation file is correct to initialze m_myStatic at runtime, but NULL is usually used for pointers, not integers, did you mean to use 0 (zero) instead?

-- ian

http://www.ian-space.com/

Navin28-Oct-02 3:56

Navin

28-Oct-02 3:56

I think the problem is that you have to initialize your static variables like you have shown:

<br />
// Somewhere in the implementation file<br />
UINT myClass::m_myStatic = NULL;<br />

You can also assign them in member functions with no problems. You don't even need to scope it. But they have to be declared like the above, or else the compiler whines.

Does that make sense? Wink | ;)

Even a broken clock is right twice a day.

alex.barylski28-Oct-02 6:42

CWnd::GetDlgItem() Question?

28-Oct-02 6:42

Hi Navin thanks for the reply...

I got it working, Smile | :)

thanx again!!!

Cheers!

"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

Old Gun27-Oct-02 20:58

Old Gun

27-Oct-02 20:58

1. Please tell me what’s wrong with my program?

// IDD_DIALOG1 is ID OF Dialog
GetDlgItem(IDD_DIALOG1)->SetWindowText(_T(“The Dialog Caption”);
…..
2.
How can I get the dialog windows pointer?

Mel Feik27-Oct-02 21:13

Mel Feik

27-Oct-02 21:13

Charlady wrote:
GetDlgItem(IDD_DIALOG1)->SetWindowText(_T(“The Dialog Caption”);

Forgive me it this turns out to be wrong as I am just hashing my through dialogs as of late but
Charlady wrote:
GetDlgItem(IDD_DIALOG1)->SetWindowText(_T(“The Dialog Caption”);
return the HANDLE in question. If you wanted it as a pointer I should think you would have no prolem assigned the HANDLE to a pointer. I do hope this helps, as I said... I'm just getting around to learning the nitty gritties of dialogs myself.
-Mel

---------------------------------------------

The greenest grass is NOT on the other side of the fence, its the grass you take care of. Have you watered your lawn lately?

ian mariano27-Oct-02 21:29

ian mariano

27-Oct-02 21:29

Are you trying to do this within a method the dialog itself? If so, all you have to do is:

SetWindowText(_T("The Dialog Caption"));

If you're trying to do this from somewhere else in your UI, say, modifying a modeless dialog, you've probably got a pointer to the dialog instance, so just call the method on the pointer:

//  m_pMyDialog is a pointer to the modeless dialog
m_pMyDialog->SetWindowText(_T("New Caption"));

Or, if you own it as a class member and not a pointer, use the . (dot) member accessor instead of the pointer one ( -> ).

GetDlgItem() is used to get child item windows of the dialog.

-- ian

http://www.ian-space.com/

Old Gun28-Oct-02 1:16

Old Gun

28-Oct-02 1:16

You are right,Thank you!

Chintan28-Oct-02 1:16

Chintan

28-Oct-02 1:16

GetDlgItem() function uses to get the handle of the controls lying on a dialog. So in this way it can't be used.

You can get the dialog handle by the m_hWnd member variable of the dialog. In the following way

" this->m_hWwn"

C.R.Naik

dialog control focus.

Mel Feik27-Oct-02 19:33

Mel Feik

27-Oct-02 19:33

Any suggestion for a better piece of code to move the focus to the next control in a dialog box? I am not using rich edits, and I tried some other things without the desired results. Somehow though, I suspect this is not the best way to go about it:

[Edit] I have this edit restricted to six characters but when I try to use the DDV max chars value to contol I get what appears an indexing problem as it moves the focus on the 7th char but that char isn't placed into the next edit which hampers continuity of the user's typing.

<br />
void CRHTC100Dlg::OnChangeId()   // my edit is IDC_ID <br />
{<br />
	CString str;<br />
	GetDlgItemText(IDC_ID,str);<br />
	if ( str.GetLength() == 6)<br />
	NextDlgCtrl();	    <br />
}//end of OnChangeId()

This just seems cumbersome to me and I'm just hoping to find some input that saves me from spending to much time researching as it does work this way.
-Mel

---------------------------------------------

The greenest grass is NOT on the other side of the fence, its the grass you take care of. Have you watered your lawn lately?

Changing CEdit font

alex.barylski27-Oct-02 18:56

27-Oct-02 18:56

What the heck am I doing wrong...?

The control isn't drawing properly when I use the following:

BOOL CEditorDlg::OnInitDialog()
{
	CDialog::OnInitDialog();

	SetIcon(m_hIcon, TRUE);			// Set big icon
	SetIcon(m_hIcon, FALSE);		// Set small icon

	CFont myFont;
	myFont.CreateFont(14, 0, 0, 0, FW_NORMAL, 
					  0, 0, 0, ANSI_CHARSET, 
					  OUT_DEFAULT_PRECIS,
					  CLIP_DEFAULT_PRECIS,
					  DEFAULT_QUALITY,
					  DEFAULT_PITCH | FF_DONTCARE,
					  "Courier New");

	CEdit* pControl = (CEdit*)GetDlgItem(IDC_EDIT1);

	ASSERT(pControl);

	pControl->SetFont(&myFont);

	return TRUE;  // return TRUE  unless you set the focus to a control
}

Can you even change a CEdit's font....? Or are you suppose to even...? I need a fixed width font...

I know this is possible cuz notepad lets you do this...and they use the same friggen class...what am I doing wrong...?

Thanx! Smile | :)

"An expert is someone who has made all the mistakes in his or her field" - Niels Bohr

Re: Changing CEdit font

Dominik Reichl27-Oct-02 22:00

Dominik Reichl

27-Oct-02 22:00

You have to make the CFont object myFont global.

Remove the declaration of myFont in the OnInitDialog function and add it to the dialog header file. The first lines in your dialog header file should read:

class CEditorDlg : public CDialog
{
// Construction
public:
	CEditorDlg(CWnd* pParent = NULL);
	CFont myFont;

Try it, it works Big Grin | :-D

-Dominik

Re: Changing CEdit font

alex.barylski28-Oct-02 6:46