Toggle buttons

Hi all,
I am making a small tool, which scans a specific file on the whole hard drive. I am making this application via a small Dialog based application. My dialog window will have three buttons "Scan", "Exit" and "About". I have a doubt

1) When user clicks the "Scan" button, the "Exit" button should change to "Stop" so the user can click this "Stop" button to stop the scan, while my tool is scanning the hard drive. Basically this "Exit" should act like TOGGLE style.

How to do this ?

Code:

---

this->GetDlgItem(IDC_STOP)->SetWindowText( "Exit");

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this is what you mean?

Cheers

Presumably, what you mean is that you don't want a user to exit while a scan is in progress.... I'd be tempted to use a slightly different logic. I think that once a scan was started, I'd change the "Scan" button to read "Stop" and I'd simply disable the "Exit" button while the app was scanning. That's only my personal preference though.

hi john, thats a nice idea.. But i would like to know, how to do this ?

Pretty much as Golanshahar indicated...

Code:

---

GetDlgItem(IDC_SCAN)->SetWindowText( "STOP" );
GetDlgItem(IDC_EXIT)->EnableWindow( FALSE );

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Of course, IDC_SCAN and IDC_EXIT would need to match your actual control ID's...!

thank you john. Now my other doubt is how to stop the scanning when the user presses the new Toggle button ("Stop") ?

Well that may depend upon the way your scan function has been implemented. I think Already we have made a lot of guess work here.....;)

Regards
Ashwin

Why don't you use radio buttons with "Push-like" style??

If I understand you correct, this is what you need :

Code:

---


bScanning = FALSE ;

void OnPressedScanButton
{
    if (!bScanning)
    {
        GetDlgItem(IDC_SCAN)->SetWindowText( "STOP" );
        GetDlgItem(IDC_EXIT)->EnableWindow( FALSE );
        bScanning = true ;
    }
    else
    {
        GetDlgItem(IDC_SCAN)->SetWindowText( "SCAN" );
        GetDlgItem(IDC_EXIT)->EnableWindow( TRUE );
        bScanning = false ;
    }
}

---

Hi all,
I am having a problem in Toggle buttons. I have a Toggle button "Scan" & "Stop". When I click "Scan" button, my app will scan the hard drive and button will change to "Stop". But, after i press "Stop" button I want to stop scanning. How to do this ? I tried using the flags. But it's not happening . How to solve this ?

You've tried using the flags?

In your Scan code, is there a while(...) or for(...) operation going on ?

If so, when the user hits "Stop", set a BOOL variable. Each time it loops through the while() operation, for example, have it check the value of that BOOL variable. If it's set, then break out of the operation.

before the operation:
BOOL bStop = FALSE;

User hits the "Stop" button, so:
bStop = TRUE;


while (...)
{
if (bStop)
break;
...
...
...

}

hi RCFOx,
I tried already as U said. but that too not happening. See my sample below:

bool Scanning = FALSE;

OnScan()
{
if(Scanning == FALSE)
{ Scanning = TRUE; }
else if(Scanning == TRUE)
{ Scanning = FALSE; }

while(EndOfDrive || Scanning != FALSE)
{
if(Scanning == FALSE){ break };
ScandDir();
}
}

void ScanDir()
{
do
{

if(Scanning == FALSE){ break };
}While(EndOfFile || Scanning != FALSE);
}


But, when I press "Stop" it's not going to OnScan().. what to do ?

Quote:

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But, when I press "Stop" it's not going to OnScan().. what to do ?

---

[/QUOTE]
I think your troubles are here:

Code:

---

bool Scanning = FALSE;

OnScan()
{
    if(Scanning == FALSE)
    {  Scanning = TRUE;  }
    else if(Scanning == TRUE)
    {  Scanning = FALSE;  }

  while(EndOfDrive || Scanning != FALSE) //<-------
  {
        if(Scanning == FALSE){ break }; <--- This only needed in ScanDir() itself 
        ScandDir();
  }
}

---

OnScan() is still executed because of the while statement. The while statement needed for the scanning has to be in your ScanDir() function so you dont need it twice. And dont run the ScanDir() in the OnScan() Send a Userdefined message to start Scandir() if ( Scanning ==TRUE) and dont send it when it is false. because the if(Scanning == FALSE){ break };

Code:

---

#define WM_EXECUTESCAN (WM_USER+1)

// This is a class member
bool Scanning = FALSE;

OnScan()
{
    if(Scanning == FALSE)
        {
        Scanning = TRUE;
        SendMessage(WM_EXECUTESCAN);
        } else
                  Scanning = FALSE; 
}

---

And then create a Handler with the wizzard ( So you can be sure he is also in the Message Map

Code:

---

OnExecuteScan()
{
ScanDir();
}

---

Jonny Poet

Quote:

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Originally Posted by Extreme_Coder

But, when I press "Stop" it's not going to OnScan().. what to do ?

---

That's because your scanning task is executed in a loop within your main (UI) thread - and that prevents the thread from processing messages, making your UI unresponsive. The usual approach to this kind of problem is to do the scanning in a worker thread.

Quote:

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Originally Posted by gstercken

The usual approach to this kind of problem is to do the scanning in a worker thread.

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Sorry I didn't look at that, but thats clear Your ScanDir() has to start a new thread, which has to be stopped when Scanning changes to false.
In VB you would have set a DoEvent() statement into the loop of ScanDir() and then it would have got the message. I never have heard about a similar solution in VC++ I'm frightened ;) there in no such an 'more easy' approach also possible in VC++ ?? If needed tell me. I'll try to do a Working thread solution for you. ( It just fits to my study to train that )



Jonny Poet

Quote:

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Originally Posted by JonnyPoet

I never have heard about a similar solution in VC++ Is there such an 'more easy' approach also possible in VC++ ??

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The usual way to do this is to provide a thread function (usually a static member function of your class) and to start a worker thread (since this seems to be an MFC app, with AfxBeginThread), passing the address of the thread function. However, this has been discussed countless times here in the forums - just do a search. Also see the following FAQs:
Hoe to create a worker thread
How to use member functions as thread functions

Quote:

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Originally Posted by gstercken

The usual way to do this is to provide a thread function (usually a static member function of your class) and to start a worker thread
...

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Hi Extrem_Coder

As gstrecken mentioned I have done a small example for you. Just an MFC Dialog based framework, done by the wizzard and the Buttons 'start/stop' and 'rest/continue'
and you can terminate pgm with 'X' in the upper right corner.

It basically shows a progressControl going from left to right.
In the working thread loop you can easily fill in his scanDir - mainloop.
If any more questions feel free to ask. When you have integrated it into your programm test every sort of terminating to be sure you didn't get any memory leaks, which may occure if the thread isn't terminated correctly too.


Jonny Poet :wave:

Quote:

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Originally Posted by JonnyPoet

When you have integrated it into your programm test every sort of terminating to be sure you didn't get any memory leaks, which may occure if the thread isn't terminated correctly too.

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:D That's an interesting approach to avoiding memory leaks...

Quote:

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Originally Posted by gstercken

:D That's an interesting approach to avoiding memory leaks...

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<lol> Its like they build games. The buyers are the testers and after 10 patches the program runs as it should be :D Hehe. Buts it seems to get industrial standard to include the customers into testphase.


Jonny Poet :wave:

Code:

---

void ScanDir()
{
    do
    {

    if(Scanning == FALSE){ break };
    }While(EndOfFile || Scanning != FALSE);  //<----
}

---

I'm assuming that this is the most nested (deepest and most busy) while operation.

The condition given to this while statement doesn't seem right. It appears the condition currently is:
"while (the end of file == true) OR (Scanning is not equal to false)".

(i don't know, your 1st condition (EndOfFile) might be correct.)

To be clearer, I think it should be:
while (!EndOfFile && Scanning == TRUE)

So, it should be: while( we're not to the end of the file AND Scanning equals true), then: it's okay to continue the operation.


Also, as mentioned, it could be that ScanDir() is so busy repeating this operation, that time isn't available to process that button click.

_

Quote:

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Originally Posted by RCFox

Code:

---

....
while (!EndOfFile && Scanning == TRUE)
...

---

---

You are totally right. In the oiginal whilestatement the loop was only done by (Sanning!=FALSE) because EndOfFile normally is FALSE as long as its not on the end. So it would never end when its not stopped from outside, because it could not be set to False because the loops in the OnScan() Statement itself didn't allow to be called again. This Method was still busy. But the mainproblem is as I described before its all one thread and VCC isn't VB where you work with DoEvents() to allow other calls in between. When you look into my file you will see an example. I did a Static counter variable and a separte thread which counts slowly up.This counting is shown by a CProgressCtrl. The value exchange between the thread and the CProgressCtrl is triggered by a timer. Also I did a start button which changes into a stop button and a rest ( wait ) button which changes between rest and continue. ( in German rest and break and wait are similar we say 'pause' or 'paused for that. I dont know which term normally is used in English. So basically it should be very easy to put a correct ScanDir() loop in which should usea Statement like you wrote.
But I havn't heard anything from Extrem_Coder. I hope he's still on the thread otherwise whatfor we are working here ? ;)


Jonny Poet :wave:

Hey all,
I am really happy to see all of your replies. I am very happy that every one takes so much concern about my problem. Really nice to see it. And hey JonnyPoet, thank you very much for the reply and I thank you, for not only giving me the solution also for providing me a sample program. Now I am gonna ask so many questions, which I feel worth and sharing all your ideas. I am basically a Information Assurance engineer and I am making a small Security analysis tool. I am gonna implement all your tips and ideas, then i will come, whether it worked out or still we gonna do some work... :) .. Thankx all.

-Regards
K.K.Senthil Velan
Information Assurance Engineer

Quote:

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Originally Posted by Extreme_Coder

Hey all,
I am gonna implement all your tips and ideas, then i will come, whether it worked out or still we gonna do some work... :) .. Thankx all.

-Regards
K.K.Senthil Velan
Information Assurance Engineer

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if any questions in doing all that stuff everytime feel free to ask, you are welcome. Its totally fine not to be a professional in that, for example I'm just on the way studying VC++ in the first year. So some things like that are a good training for me. ;)

And if you are satisfied feel free to rate the posts which was helpful for you ( thats i the upper right corner of each post. ) To be rated ist just the milk for all the helpers do this :)


Jonny Poet :wave: