C / C++ / MFC

3-Jan-06 3:37

Inherit CMyCDialog class in Class X (Class X : public CMyDialog)??. but the problem is the class X has been already inherited by the CMyDialog Call. so if do so, it'll become a cyclic inheritance. u cant do that. how to go about here?

scenario:

in Class X i have two methods

<br />
class X<br />
{<br />
SendData();<br />
ReceiveData();<br />
}<br />

In my CMyDialog, (which looks like class CMyDialod: public X)

i'd call in a button click,

<br />
void CMyDialog::OnClick()<br />
{<br />
this->SendData();<br />
}<br />

this works fine.

but when receiving , i want to display them in the CDialog. the function ReceiveData is a Thread. so in the middle of the thread, i need to update the status in the CDialog's textboxes.

in short, is it possible to access the members of the child class? or any direct access?

thanks,

"But your mind is very complex, very tricky. It makes simple things complicated. -- that's its work. And for centuries it has been trained for only one thing: to make things so complicated that your life becomes impossible."- Osho

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benjymous3-Jan-06 4:48

benjymous

3-Jan-06 4:48

You need to use virtual functions - a function that is defined in the base class, but implemented in the derived class, like so:

<br />
class X:<br />
{<br />
  SendData();<br />
  RecieveData();<br />
<br />
  virtual void UpdateDialog(int message) = 0; // This is a pure virtual - no implementation in class X<br />
}<br />
<br />
X::RecieveData()<br />
{<br />
  UpdateDialog();  // This will perform the UpdateDialog functionality defined in CDialog below<br />
}<br />
<br />
<br />
class CMyDialog : public X<br />
{<br />
  virtual void UpdateDialog(int message);<br />
}<br />
<br />
CMyDialog::UpdateDialog(int message)<br />
{<br />
  //Update your dialog here!<br />
}<br />

--
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Buzzwords!

Eytukan3-Jan-06 4:58

3-Jan-06 4:58

i'll try this . thanks.

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Prakash Nadar3-Jan-06 5:05

Prakash Nadar

3-Jan-06 5:05

You might have problem accessing the dialog window (in MFC) from another thread, so you have to use the HWND to directly access the control , or post (userdefined) message to the dialog window from the thread which will update the information.

-Prakash

Eytukan3-Jan-06 5:10

3-Jan-06 5:10

yeaa.. this is another useful tip. thanks prakash. Smile | :)

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thread/application priority

S Douglas3-Jan-06 20:25

S Douglas

3-Jan-06 20:25

I agree with Mr. Prakash, this sounds like a clear case for sending messages.

take a look at this article. Message Management[^]

Using User-Interface Threads[^]

ZeePain! wrote:
This seems like one of those programs that started small, grew incrementally, building internal pressure, and finally barfed all over its source code sneakers. Or something.

thedailywtf.com[^]

tonyro3-Jan-06 3:30

tonyro

3-Jan-06 3:30

I'm trying to write a very time sensitive program so I need to make sure that the entire application receives the highest of priorities and that no background tasks are running. I tried using 'SetThreadPriority(hWnd,31);', but other tasks, processes, applications, etc still seem to run and interfere with the timing of my program. Is it possible to make my program such that it is the only task that is running on the computer? Thanks in advance for any help.

khan++3-Jan-06 3:42

khan++

3-Jan-06 3:42

I think you could also try:
BOOL SetPriorityClass(HANDLE hProcess,DWORD dwPriorityClass);
But in my opinion, there is no way you could stop operating system processes from executing.
But boosting the priority to very high could easily hang the system...Oh I see that is exactly what you are trying to do, right?

this is this.

Ali Mojtabaee3-Jan-06 3:50

Ali Mojtabaee

3-Jan-06 3:50

tonyro wrote:
Is it possible to make my program such that it is the only task that is running on the computer?

I don't think so.there are many OS tasks that manage your system and you can not stop them , if you try to stop them (if you can!) the system may crash or go to an unstable condition.can you tell me the smallest unit of time you use in your program?

tonyro3-Jan-06 3:53

tonyro

3-Jan-06 3:53

Thanks for your response. I'm trying to get all events in the program to be accurate down to the one millisecond scale.

basementman3-Jan-06 4:59

basementman

3-Jan-06 4:59

Windows is NOT a real-time OS. So, the best you could hope for is around a 10-20 ms scale.

onwards and upwards...

Ali Mojtabaee4-Jan-06 5:43

Ali Mojtabaee

4-Jan-06 5:43

Windows is not a real-time OS, It’s true! But there are techniques to satisfy timing constraints of a windows real-time application with 1 millisecond accuracy. Some of them may be complex and hard to implement but they are possible.
see this on MSDN: http://msdn.microsoft.com/library/en-us/dnxpembed/html/hardrealtime.asp[^]

-- modified at 0:47 Thursday 5th January, 2006

Michael Dunn3-Jan-06 7:44

Michael Dunn

3-Jan-06 7:44

tonyro wrote:
Is it possible to make my program such that it is the only task that is running on the computer?

Imagine if this were possible:
* How would the screen get drawn?
* How would the system read keyboard/mouse input?
* How would the system access the hard drive?
* How would the system manage the swap file?

Windows is the wrong OS for your task.

--Mike--
Visual C++ MVP Cool | :cool:

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tonyro4-Jan-06 4:53

tonyro

4-Jan-06 4:53

This is why I continue to use Windows 98 on some systems and Exit to DOS, where I can control all of these functions. However, it is getting more and more difficult to maintain those machines. What modern OS would you recommend?

Michael Dunn5-Jan-06 9:16

Michael Dunn

5-Jan-06 9:16

You can still run 98 on computers you can buy today. If 98 and DOS work for you, why change?

--Mike--
Visual C++ MVP Cool | :cool:

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problem with buffer in fread and fwrite

Stephen Hewitt9-Jan-06 2:04

Stephen Hewitt

9-Jan-06 2:04

http://www.sysinternals.com/Information/TipsAndTrivia.html Look for "Never-ending Quantum?".

NOTE: I only add this for interests sake. The users of you program will not thank you for disabling multitasking on his machine. Basically here's how to do it but by the way, don't do it. I haven't actually tried it myself, just came across it in my travels.

Steve

hamsha_ir3-Jan-06 2:38

hamsha_ir

3-Jan-06 2:38

Hi everyone
I have some problem with fread and fwrite in VS2005 beta2
I have the following code, in it i generate a buffer and after assigning some values to it , i write it to a file , then i try to read it back to a new buffer which is not successful.
for variable bigVal=100 i get "k=100" for writing but for reading i get "k=77" , i would be pleased if someone can help me.

#include "stdafx.h"
#include <stdlib.h>
#include <time.h>
#include <stdio.h>

typedef double dtype;

int _tmain(int argc, _TCHAR* argv[])
{

dtype *b;
int i,j,k;
int bigVal;
char filename[]="c:\\temp.data";
FILE *fp;

bigVal=100;
b=(dtype*) malloc(bigVal * sizeof(dtype));

for(i=0 ; i

Re: problem with buffer in fread and fwrite

kakan3-Jan-06 2:56

kakan

3-Jan-06 2:56

Hello.
I'm not sure if it's your only problem, but you should definately use binary mode for your files. So use:
fopen(filename,"wb")
and
fopen(filename,"rb")

Kakan

Re: problem with buffer in fread and fwrite

Laxman93-Jan-06 2:59

Laxman9

3-Jan-06 2:59

in fread and fwrite the first parameter is "void *" so try typecasting the first parameter as following

fread((void*)b,sizeof(dtype),bigVal,fp);
fwrite((void*)b,sizeof(dtype),bigVal,fp);

it worked when i tried past. Smile | :)

FAILURE is the first step towards SUCCESS

Simulating a click in a CListCtrl

Kharfax3-Jan-06 1:47

Kharfax

3-Jan-06 1:47

Hi
The CListCtrl click handler shows an edit box that allows to edit the subitem values. That is working fine when I click using the mouse.

But now, I need to simulate a click in a ClistCtrl, to open that edit box automatically.

I already tried using mouse_event but the mouse pointer appears in the task bar, and nothing else happens.

So, I think, I should call the CListCtrl click handler.

OnClick(NMHDR* pNMHDR, LRESULT* pResult)

The NMHDR* really is a NMITEMACTIVATE pointer.

So I filled the ptAction, iItem, and iSubitem and created a LRESULT variable.

Then I call OnClick((NMHDR*)struct, &lResult);

The handler is called, but the edit doesn't appear, and when I close the application it hangs up, and tell me if want to tell it to Bill Gates Wink | ;)

Any suggestion really appreciated, and thanks for reading all that Big Grin | :-D

Sebastian

Re: Simulating a click in a CListCtrl

khan++3-Jan-06 2:44

khan++

3-Jan-06 2:44

You could send a direct message to the list ctrl, like:

m_List.SendMessage(WM_LBUTTONDOWN,0,MAKELPARAM(2,20));<br />
Sleep(100);<br />
m_List.SendMessage(WM_LBUTTONUP,0,MAKELPARAM(2,20));

However, the mouse-location (2,20) must be correct for it to work properly. Most probably you want an item to be selected also, which means that you have to calculate the item's correct location in the list ctrl.

An alternative would be to select an item in the list ctrl through code, and take its text and show the edit box yourself, without depending on the click-handler.

this is this.

Re: Simulating a click in a CListCtrl

Eytukan3-Jan-06 5:25