Pointer to CWnd* - why does not this work? [modified] - C / C++ / MFC Discussion Boards

raju_Code wrote:
imgout.BitBlt(hdc,0,694);
imgout.ReleaseDC();
imgout.Save(L"Sample.tif");

I suppose you should use

imgout.Create(624, 694, __ImageZoom.getBPP());
__ImageZoom.StretchBlt(imgout.getDC(), 0, 0, 624, 694);
imgout.ReleaseDC();
imgout.Save(L"Sample.tif");

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

modified on Tuesday, September 29, 2009 5:05 AM

Thanks for your replay

when i add your function ..its throwing exception like

m_hBitmap!=0

You're right, I missed a step. Anyway I've fixed my previous answer, check it out.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Thanks mr.CPallini

i solved it ...

~~~~~~~~~~~~~Raju~~~~~~~~~~~~~

I have A Main Application . I have another second exe , that second exe will run using create
process() through main application by clicking on button . Is that possible I can run the second

exe on another computer in network as I click button on main Application

Trioum

Nope, not with CreateProcess.

It is a crappy thing, but it's life -^ Carlo Pallini

then how it is possible .tell me another procedure

Trioum

Hello!

Cannot figure this out for two days already...

Example:

Header file:

<br />
<br />
#pragma once<br />
#include "afxwin.h"<br />
#include "afxcmn.h"<br />
<br />
<br />
// CUsersForm dialog<br />
<br />
class CUsersForm : public CDialog<br />
{<br />
	DECLARE_DYNAMIC(CUsersForm)<br />
<br />
public:<br />
	CUsersForm(CWnd* pParent = NULL);   // standard constructor<br />
	virtual ~CUsersForm();<br />
<br />
// Dialog Data<br />
	enum { IDD = IDD_USERS_FORM };<br />
<br />
protected:<br />
	virtual void DoDataExchange(CDataExchange* pDX);    // DDX/DDV support<br />
<br />
	DECLARE_MESSAGE_MAP()<br />
public:<br />
<br />
        afx_msg void OnBnClickedGendataButton();<br />
<br />
	CWnd* GenDataButton;<br />
	<br />
	void InitDataFields(void);<br />
	virtual BOOL OnInitDialog();<br />
};<br />
<br />
<br />

Code file:

// UsersForm.cpp : implementation file<br />
//<br />
<br />
#include "stdafx.h"<br />
#include "UsersForm.h"<br />
<br />
<br />
// CUsersForm dialog<br />
<br />
IMPLEMENT_DYNAMIC(CUsersForm, CDialog)<br />
<br />
CUsersForm::CUsersForm(CWnd* pParent /*=NULL*/)<br />
	: CDialog(CUsersForm::IDD, pParent)<br />
{<br />
<br />
}<br />
<br />
CUsersForm::~CUsersForm()<br />
{<br />
}<br />
<br />
<br />
void CUsersForm::DoDataExchange(CDataExchange* pDX)<br />
{<br />
	CDialog::DoDataExchange(pDX);<br />
}<br />
<br />
<br />
BEGIN_MESSAGE_MAP(CUsersForm, CDialog)<br />
	ON_BN_CLICKED(IDC_GENDATA_BUTTON, &CUsersForm::OnBnClickedGendataButton)<br />
END_MESSAGE_MAP()<br />
<br />
void CUsersForm::OnBnClickedGendataButton()<br />
{	<br />
	this->GenDataButton->ShowWindow(SW_HIDE);<br />
        //Why isn`t the GenDataButton valid here???<br />
}<br />
<br />
<br />
BOOL CUsersForm::OnInitDialog()<br />
{<br />
	CDialog::OnInitDialog();<br />
	this->InitDataFields();<br />
	return TRUE;  // return TRUE unless you set the focus to a control<br />
	// EXCEPTION: OCX Property Pages should return FALSE<br />
}<br />
<br />
void CUsersForm::InitDataFields(void)<br />
{<br />
	this->GenDataButton = GetDlgItem(IDC_GENDATA_BUTTON);<br />
        //Debugging shows that GenDataButton is valid here.<br />
<br />
}

The point is - this is just a sample code. I need to create an array of pointers to dialog items (CWnd type) for later use in this class. How do i accomplish this?

Please at least point me to the right documentation about this issue.. Is this something with variable types (static etc)..

Thank`s

modified on Tuesday, September 29, 2009 7:12 AM

Makakuin wrote:
void CUsersForm::InitDataFields(void)
{
this->GenDataButton = GetDlgItem(IDC_GENDATA_BUTTON)->m_hWnd;
//Debugging shows that GenDataButton is valid here.

}

GenDataButton is a CWnd*, not a HWND. So, write this instead:

this->GenDataButton = GetDlgItem(IDC_GENDATA_BUTTON);

Cédric Moonen
Software developer

Charting control [v2.0]
OpenGL game tutorial in C++

Makakuin wrote:
this->GenDataButton = GetDlgItem(IDC_GENDATA_BUTTON)->m_hWnd;

How can this line compile?

Why don't you map a control variable using the Add member Variable Wizard of Visual Studio?
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke

[My articles]

Sorry - I`ve tried this also - does not work - the GendataButton is valid right after the call to InitDataFields -

if I call InitDataFields() just before a call to GenDataButton->ShowWindow(SW_HIDE) - it works, bu after exiting the OnGenDataButton scope the GenDataButton pointer is emtpy..

Hi All

How can i read environment variable rom c program

Mohan t

modified on Tuesday, September 29, 2009 2:19 AM

If you are under windows (using VC++) then you can use GetEnvironmentVariable[^]. Otherwise maybe give getenv[^] a try.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Sometimes you just have to hate coding to do it well. <

Every C program takes 3 arguments on the main function.
The 3rd parameter is a pointer to the environment block.

int main(int argc, char* argv[], char* envp[])
{
    // envp  is an array of string to the environment block.

    return 0;
}

«_Superman_»
I love work. It gives me something to do between weekends.

Hi Experts,

I want a CListCtrl with Checkbox and Report View in which some item should be selectable and remaining should not.

How can I do that?

Try handling the LVN_ITEMCHANGING[^] notification, examine which item is about to change anf if it is one that is not allowed, return TRUE to prevent the selection/checking. Hope that is what you need...

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Sometimes you just have to hate coding to do it well. <

But I want also make these item different(Not Selectable) from other List Item(Selectable).

Then you will have to go with ownerdrawn[^] items i believe.

> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> Sometimes you just have to hate coding to do it well. <

Hi to All,

In regards to previous problem of mine,...I have made an overloaded construtor of dialog class in dialogB...Now while creating the object of the dialog , I am passing the variables...No problem the overloaded contrctor of dialogB calls fine. But again, the default constructor is getting called. Why so?

my code line to create the dialog is...

dialogB obj = new dialogB(&m_boardMainPage,&m_portMainPage,&m_extMainPage);
obj.DoModal();

I need to create the dialog with overloaded constructor (in order to pass some valued to that dialog)..Please help me.

-----------------------------
I am a beginner

You have classA, and classB inheriting from that.
You make a new classB, and both classB::classB() and classA::classA() are getting called?

This is not a bad thing. This is a GOOD thing.

Imagine if this was not the case. CDialog is a slightly complex class. You make a new dialog. Your constructor would have to do all the special work of your new class. AND ann the special work of a CDialog. AND all the special work of a CWnd. AND all the special work of a CObject.

(It's turtles all the way down).

If you want to control which CDialog constructor gets called, you need to do the following:

CMyDlg::CMyDlg (CWnd *pParent)
: CDialog (IDD_MYDLG, pParent)   // take this line out, and CDialog::CDialog () will get called.
{

In addition - the base class constructor gets called first. Again, imagine if it was the other way around. All the stuff not included in the inheriting class would be uninitialised.

I hope that helps,

Iain.

I have now moved to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), or need contract work done, give me a job! http://cv.imcsoft.co.uk/[^]

A guess what's causing this behavior: If you pass a variable of class dialogB in a function call, the default constructor will be called to create a second instance of dialogB.

If this is happening and you want to avoid this behavior, pass the address of the dialogB object, rather than the object itself.

Hi to All,

Could anyone please help me with my following problem.

Basically, I need a way to pass values between different dialog. Following is exactly what my requirement is.....

I have a property page, from where I am opening an another dialog (modal), to enter some values. Now I want those values back in my property page, once the user closes the modal dialog. PLease help me with it.

Thanks in advance.

-----------------------------
I am a beginner

You can use 'SendMessage()'function

thanks for your reply..
Could u please elaborate a little bit.I am new to MFC

Thanks

-----------------------------
I am a beginner

This is pretty classic MFC stuff.

You have a propert page called CMyPropertyPage. It has two controls on it.
1) A button called "press me". Use class wizard to associate this with a function OnPressMe.
2) An edit control (or a static control, I don;t care). Again, classwizard, associate with a CString called m_hrishiS.

When you press the button, you want a dialog box to pop up. This box has been made already, and is called CMyDlg. This has a single edit control on it. Using class wizard, you've associated this edit control with a class member m_MyString.

So, your function would be like...

void CMyPropertyPage::OnPressMe () // class wizard has made this with your guidance
{
   UpdateData (TRUE); // get the data on the page into the member data

   CMyDlg dlg (this); // make a new dialog box, and this page is its parent window.
   dlg.m_MyString = m_hrishiS;  // copy the string from the property page to the dialog.

   if (dlg.DoModal () != IDOK)  // run the dialog, and check our return value
      return;

   m_hrishiS = dlg.m_MyString;  // copy the string from the dialog to the property page.

  UpdateData (FALSE); // put the data in the string back on to the propertypage.
}

Now go back to your book, or the MFC manual pages, and look up UpdateData. Also read the code for DoDataExchange that has been created automatically for you, and look up DDX_Text in the manual.

I hope this steers you in the right direction.

Iain.

I have now moved to Sweden for love (awwww).
If you're in Scandinavia and want an MVP on the payroll (or happy with a remote worker), or need contract work done, give me a job! http://cv.imcsoft.co.uk/[^]