C / C++ / MFC

30-Sep-19 21:38

In the below code snippet, why do we use '&' ? Is it because we're passing the reference of the member function?

C++

BEGIN_MESSAGE_MAP(CMFCListViewDoc, CDocument)
   ON_COMMAND(ID_MYCOMMAND, &CMFCListViewDoc::OnMycommand) // why do we use '&'
END_MESSAGE_MAP()

Excuse me for this question. It's like I know and I don't know too Smile | :)

Re: Message_Map MFC vc++

CPallini30-Sep-19 21:56

CPallini

30-Sep-19 21:56

&CMFCListViewDoc::OnMycommand is a pointer to the member function.
See, for instance IBM Knowledge Center: Pointers to members (C++ only)[^]

c programming

Member 1460831330-Sep-19 6:47

Member 14608313

30-Sep-19 6:47

I want to get a positive integer from the user.

phil.o30-Sep-19 7:09

phil.o

30-Sep-19 7:09

"I want" is not a question.

"Five fruits and vegetables a day? What a joke!
Personally, after the third watermelon, I'm full."

Dave Kreskowiak30-Sep-19 7:13

Dave Kreskowiak

30-Sep-19 7:13

There's only about a couple dozen different ways to do that, depending on the application type you're writing and the context in which you're getting this input.

Without a lot more detail about what you're doing, anything anyone replies with will be just guess work that will probably not work in your situation.

Asking questions is a skill
CodeProject Forum Guidelines
Google: C# How to debug code
Seriously, go read these articles.

Dave Kreskowiak

Victor Nijegorodov30-Sep-19 9:16

30-Sep-19 9:16

Do it!
Good luck! Smile | :)

How to hide or show button from another class MFC vc++

CPallini30-Sep-19 10:48

CPallini

30-Sep-19 10:48

You could start from

#include <stdio.h>

int main()
{
  int i;
  for (;;)
  {
    printf("please enter a positive integer\n");
    if ( scanf("%d", &i) == 1 && i > 0 ) break;
  }
  printf("you entered %d, a good one\n", i);
  return 0;
}

and then find a better way...

Member 1457555630-Sep-19 4:44

Re: How to hide or show button from another class MFC vc++

30-Sep-19 4:44

How can I access controls of one class from another class.
Example, Initially the button is hidden. I tried to make it visible from another class by doing like this

C++

GetDlgItem(IDC_BUTTON)->ShowWindow(TRUE);

inside a function.

But this doesn't seem to work. How can I make it visible from another class.

Thanks in advance.

Victor Nijegorodov30-Sep-19 4:51

Re: How to hide or show button from another class MFC vc++

30-Sep-19 4:51

Member 14575556 wrote:
But this doesn't seem to work.

What exactly "doesn't seem to work"?
Could you show your code?

Member 1457555630-Sep-19 5:10

Re: How to hide or show button from another class MFC vc++

30-Sep-19 5:10

There are two button in Dialog 1.

C++

BOOL CMyFirstDlg::OnInitDialog()
{
CDialogEx::OnInitDialog();
GetDlgItem(IDC_BUTTON)->ShowWindow(FALSE);

ShowWindow(SW_MINIMIZE);


return TRUE;  
}

When I click one button i want to make the other button visible again.

C++

void CMyFirstDlg::OnBnClickedButton()
{
  CSecondDlg* Obj = new CSecondDlg();
  Obj->DisplayButton();
}

Inside the DisplayButton function which is in another class there is

C++

GetDlgItem(IDC_BUTTON)->ShowWindow(TRUE);

Victor Nijegorodov30-Sep-19 5:17

Re: How to hide or show button from another class MFC vc++

30-Sep-19 5:17

Member 14575556 wrote:
When I click one button i want to make the other button visible again.

C++
void CMyFirstDlg::OnBnClickedButton()
{
  CSecondDlg* Obj = new CSecondDlg();
  Obj->DisplayButton();
}

You created the object of CSecondDlg class but you have not created the window of this dialog!

David Crow30-Sep-19 6:09

David Crow

30-Sep-19 6:09

Member 14575556 wrote:
CSecondDlg* Obj = new CSecondDlg();
Obj->DisplayButton();

See here.

"One man's wage rise is another man's price increase." - Harold Wilson

"Fireproof doesn't mean the fire will never come. It means when the fire comes that you will be able to withstand it." - Michael Simmons

"You can easily judge the character of a man by how he treats those who can do nothing for him." - James D. Miles

Re: How to hide or show button from another class MFC vc++

David Crow30-Sep-19 6:06

David Crow

30-Sep-19 6:06

Member 14575556 wrote:
How can I access controls of one class from another class.

Your question should probably be something like, "How can I access controls on one dialog from a separate dialog?" While it is not a good idea to do so directly (see "loose coupling"), a better way would be to send a message to the parent (the one that owns the control) dialog.

Re: How to hide or show button from another class MFC vc++

Member 1457555630-Sep-19 19:58

Creating separate class for database connection MFC vc++

30-Sep-19 19:58

Thank you for the pointing me to the right direction. Smile | :)

I'll read about "loose coupling" and to be honest I don't really get how to send message as of now, so I'll read about that too.

I've solve my problem in a naive way for now but i'll definitely follow your suggestions.

Thanks again.

Member 1457555626-Sep-19 19:59

Re: Creating separate class for database connection MFC vc++

26-Sep-19 19:59

I have created a simple dialog application where it can perform crud operations but how I did it was I open a connection an do some operations inside most of the buttons as I'm still starting out as a beginner(noob).

What will be a good approach to separate all the database related operations in another class? or keeping as it is, is it a good practice?

I would like some suggestions.

Thank you.

Gerry Schmitz26-Sep-19 20:08

Gerry Schmitz

26-Sep-19 20:08

Since you're asking the question, you probably already know the answer.

The Master said, 'Am I indeed possessed of knowledge? I am not knowing. But if a mean person, who appears quite empty-like, ask anything of me, I set it forth from one end to the other, and exhaust it.'
― Confucian Analects

Re: Creating separate class for database connection MFC vc++

David Crow27-Sep-19 7:58

David Crow

27-Sep-19 7:58

I did something similar here. It may not be exactly what you are after, but it does give you another perspective, which could ultimately get you to your goal.

cannot change rgrc0 with wm_nccalcsize

Member 1180360726-Sep-19 7:26

Member 11803607

26-Sep-19 7:26

we want to decrease right of non client area in edit control and draw edge in that but wparam in nccalcsize return 1 only not 0 and lparam no give us rgrc0 or rgrc1 value to change it , if somebody try this please tell me its way and show the pictures to do like this

Richard MacCutchan26-Sep-19 7:47

Richard MacCutchan

26-Sep-19 7:47

Please edit your question and show the code you are using, and explain what happens when you run it.

Member 1180360726-Sep-19 8:41

Member 11803607

26-Sep-19 8:41

case win.WM_NCCALCSIZE:

if wParam > 0
{ params := (*win.NCCALCSIZE_PARAMS)(unsafe.Pointer(lParam))

params.Rgrc[0].Top=params.Rgrc[2].Top params.Rgrc[0].Left = params.Rgrc[0].Left + 1
params.Rgrc[0].Bottom=params.Rgrc[0].Bottom-1
params.Rgrc[0].Right=params.Rgrc[0].Right-10

Victor Nijegorodov26-Sep-19 9:33

26-Sep-19 9:33

And where do you handle this message?

Member 11803607 wrote:
if wParam > 0
{ params := (*win.NCCALCSIZE_PARAMS)(unsafe.Pointer(lParam))

What does this

Quote:
:=

mean?

Member 1180360726-Sep-19 9:43

Member 11803607

26-Sep-19 9:43

wm_nccalcsize Sent when use swp_framechanged in SetWindowPos ( Draw New Style )

i want to decrease the right of client rect to use drawEge in that space was made

Victor Nijegorodov26-Sep-19 10:08